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psutil

Giampaolo Rodola' <grodola@gmail.com>

psutil documentation

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About

psutil (python system and process utilities) is a cross-platform library for retrieving information on running processes and system utilization (CPU, memory, disks, network, sensors) in Python. It is useful mainly for system monitoring, profiling, limiting process resources and the management of running processes. It implements many functionalities offered by UNIX command line tools such as: ps, top, lsof, netstat, ifconfig, who, df, kill, free, nice, ionice, iostat, iotop, uptime, pidof, tty, taskset, pmap. psutil currently supports the following platforms:

• Linux
• Windows
• macOS
• FreeBSD, OpenBSD, NetBSD
• Sun Solaris
• AIX

Supported Python versions are 2.6, 2.7 and 3.4+. PyPy is also known to work.

The psutil documentation you're reading is distributed as a single HTML page.

Funding

While psutil is free software and will always be, the project would benefit immensely from some funding. Keeping up with bug reports and maintenance has become hardly sustainable for me alone in terms of time. If you're a company that's making significant use of psutil you can consider becoming a sponsor via GitHub, Open Collective or PayPal and have your logo displayed in here and psutil doc.

Sponsors

^{add your logo}

Supporters

None yet.

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Install

Linux Ubuntu / Debian:

sudo apt-get install gcc python3-dev
sudo pip3 install psutil

Linux Redhat:

sudo yum install gcc python3-devel
sudo pip3 install psutil

Windows:

pip3 install psutil

For other platforms see more detailed install instructions.

System related functions

CPU

cpu_times(percpu=False)

Return system CPU times as a named tuple. Every attribute represents the seconds the CPU has spent in the given mode. The attributes availability varies depending on the platform:

• user: time spent by normal processes executing in user mode; on Linux this also includes guest time
• system: time spent by processes executing in kernel mode
• idle: time spent doing nothing

Platform-specific fields:

• nice (UNIX): time spent by niced (prioritized) processes executing in user mode; on Linux this also includes guest_nice time
• iowait (Linux): time spent waiting for I/O to complete. This is not accounted in idle time counter.
• irq (Linux, BSD): time spent for servicing hardware interrupts
• softirq (Linux): time spent for servicing software interrupts
• steal (Linux 2.6.11+): time spent by other operating systems running in a virtualized environment
• guest (Linux 2.6.24+): time spent running a virtual CPU for guest operating systems under the control of the Linux kernel
• guest_nice (Linux 3.2.0+): time spent running a niced guest (virtual CPU for guest operating systems under the control of the Linux kernel)
• interrupt (Windows): time spent for servicing hardware interrupts ( similar to "irq" on UNIX)
• dpc (Windows): time spent servicing deferred procedure calls (DPCs); DPCs are interrupts that run at a lower priority than standard interrupts.

When percpu is True return a list of named tuples for each logical CPU on the system. First element of the list refers to first CPU, second element to second CPU and so on. The order of the list is consistent across calls. Example output on Linux:

>>> import psutil >>> psutil.cpu_times() scputimes(user=17411.7, nice=77.99, system=3797.02, idle=51266.57, iowait=732.58, irq=0.01, softirq=142.43, steal=0.0, guest=0.0, guest_nice=0.0)

4.1.0 added interrupt and dpc fields on Windows.

cpu_percent(interval=None, percpu=False)

Return a float representing the current system-wide CPU utilization as a percentage. When interval is > 0.0 compares system CPU times elapsed before and after the interval (blocking). When interval is 0.0 or None compares system CPU times elapsed since last call or module import, returning immediately. That means the first time this is called it will return a meaningless 0.0 value which you are supposed to ignore. In this case it is recommended for accuracy that this function be called with at least 0.1 seconds between calls. When percpu is True returns a list of floats representing the utilization as a percentage for each CPU. First element of the list refers to first CPU, second element to second CPU and so on. The order of the list is consistent across calls.

>>> import psutil >>> # blocking >>> psutil.cpu_percent(interval=1) 2.0 >>> # non-blocking (percentage since last call) >>> psutil.cpu_percent(interval=None) 2.9 >>> # blocking, per-cpu >>> psutil.cpu_percent(interval=1, percpu=True) [2.0, 1.0] >>>

Warning

the first time this function is called with interval = 0.0 or None it will return a meaningless 0.0 value which you are supposed to ignore.

cpu_times_percent(interval=None, percpu=False)

Same as cpu_percent() but provides utilization percentages for each specific CPU time as is returned by psutil.cpu_times(percpu=True)<cpu_times()>. interval and percpu arguments have the same meaning as in cpu_percent(). On Linux "guest" and "guest_nice" percentages are not accounted in "user" and "user_nice" percentages.

Warning

the first time this function is called with interval = 0.0 or None it will return a meaningless 0.0 value which you are supposed to ignore.

4.1.0 two new interrupt and dpc fields are returned on Windows.

cpu_count(logical=True)

Return the number of logical CPUs in the system (same as os.cpu_count in Python 3.4) or None if undetermined. logical cores means the number of physical cores multiplied by the number of threads that can run on each core (this is known as Hyper Threading). If logical is False return the number of physical cores only (Hyper Thread CPUs are excluded) or None if undetermined. On OpenBSD and NetBSD psutil.cpu_count(logical=False) always return None. Example on a system having 2 physical hyper-thread CPU cores:

>>> import psutil >>> psutil.cpu_count() 4 >>> psutil.cpu_count(logical=False) 2

Note that this number is not equivalent to the number of CPUs the current process can actually use. That can vary in case process CPU affinity has been changed, Linux cgroups are being used or on Windows systems using processor groups or having more than 64 CPUs. The number of usable CPUs can be obtained with:

>>> len(psutil.Process().cpu_affinity()) 1

cpu_stats()

Return various CPU statistics as a named tuple:

• ctx_switches: number of context switches (voluntary + involuntary) since boot.
• interrupts: number of interrupts since boot.
• soft_interrupts: number of software interrupts since boot. Always set to 0 on Windows and SunOS.
• syscalls: number of system calls since boot. Always set to 0 on Linux.

Example (Linux):

>>> import psutil
>>> psutil.cpu_stats()
scpustats(ctx_switches=20455687, interrupts=6598984, soft_interrupts=2134212, syscalls=0)

4.1.0

cpu_freq(percpu=False)

Return CPU frequency as a nameduple including current, min and max frequencies expressed in Mhz. On Linux current frequency reports the real-time value, on all other platforms it represents the nominal "fixed" value. If percpu is True and the system supports per-cpu frequency retrieval (Linux only) a list of frequencies is returned for each CPU, if not, a list with a single element is returned. If min and max cannot be determined they are set to 0.

Example (Linux):

>>> import psutil
>>> psutil.cpu_freq()
scpufreq(current=931.42925, min=800.0, max=3500.0)
>>> psutil.cpu_freq(percpu=True)
[scpufreq(current=2394.945, min=800.0, max=3500.0),
 scpufreq(current=2236.812, min=800.0, max=3500.0),
 scpufreq(current=1703.609, min=800.0, max=3500.0),
 scpufreq(current=1754.289, min=800.0, max=3500.0)]

Availability: Linux, macOS, Windows, FreeBSD

5.1.0

5.5.1 added FreeBSD support.

getloadavg()

Return the average system load over the last 1, 5 and 15 minutes as a tuple. The "load" represents the processes which are in a runnable state, either using the CPU or waiting to use the CPU (e.g. waiting for disk I/O). On UNIX systems this relies on os.getloadavg. On Windows this is emulated by using a Windows API that spawns a thread which keeps running in background and updates results every 5 seconds, mimicking the UNIX behavior. Thus, on Windows, the first time this is called and for the next 5 seconds it will return a meaningless (0.0, 0.0, 0.0) tuple. The numbers returned only make sense if related to the number of CPU cores installed on the system. So, for instance, a value of 3.14 on a system with 10 logical CPUs means that the system load was 31.4% percent over the last N minutes.

>>> import psutil
>>> psutil.getloadavg()
(3.14, 3.89, 4.67)
>>> psutil.cpu_count()
10
>>> # percentage representation
>>> [x / psutil.cpu_count() * 100 for x in psutil.getloadavg()]
[31.4, 38.9, 46.7]

Availability: Unix, Windows

5.6.2

Memory

virtual_memory()

Return statistics about system memory usage as a named tuple including the following fields, expressed in bytes. Main metrics:

• total: total physical memory (exclusive swap).
• available: the memory that can be given instantly to processes without the system going into swap. This is calculated by summing different memory values depending on the platform and it is supposed to be used to monitor actual memory usage in a cross platform fashion.

Other metrics:

• used: memory used, calculated differently depending on the platform and designed for informational purposes only. total - free does not necessarily match used.
• free: memory not being used at all (zeroed) that is readily available; note that this doesn't reflect the actual memory available (use available instead). total - used does not necessarily match free.
• active (UNIX): memory currently in use or very recently used, and so it is in RAM.
• inactive (UNIX): memory that is marked as not used.
• buffers (Linux, BSD): cache for things like file system metadata.
• cached (Linux, BSD): cache for various things.
• shared (Linux, BSD): memory that may be simultaneously accessed by multiple processes.
• slab (Linux): in-kernel data structures cache.
• wired (BSD, macOS): memory that is marked to always stay in RAM. It is never moved to disk.

The sum of used and available does not necessarily equal total. On Windows available and free are the same. See meminfo.py script providing an example on how to convert bytes in a human readable form.

Note

if you just want to know how much physical memory is left in a cross platform fashion simply rely on the available field.

>>> import psutil >>> mem = psutil.virtual_memory() >>> mem svmem(total=10367352832, available=6472179712, percent=37.6, used=8186245120, free=2181107712, active=4748992512, inactive=2758115328, buffers=790724608, cached=3500347392, shared=787554304, slab=199348224) >>> >>> THRESHOLD = 100 * 1024 * 1024 # 100MB >>> if mem.available <= THRESHOLD: ... print("warning") ... >>>

4.2.0 added shared metric on Linux.

5.4.4 added slab metric on Linux.

swap_memory()

Return system swap memory statistics as a named tuple including the following fields:

• total: total swap memory in bytes
• used: used swap memory in bytes
• free: free swap memory in bytes
• percent: the percentage usage calculated as (total - available) / total * 100
• sin: the number of bytes the system has swapped in from disk (cumulative)
• sout: the number of bytes the system has swapped out from disk (cumulative)

sin and sout on Windows are always set to 0. See meminfo.py script providing an example on how to convert bytes in a human readable form.

>>> import psutil >>> psutil.swap_memory() sswap(total=2097147904L, used=886620160L, free=1210527744L, percent=42.3, sin=1050411008, sout=1906720768)

5.2.3 on Linux this function relies on /proc fs instead of sysinfo() syscall so that it can be used in conjunction with psutil.PROCFS_PATH in order to retrieve memory info about Linux containers such as Docker and Heroku.

Disks

disk_partitions(all=False)

Return all mounted disk partitions as a list of named tuples including device, mount point and filesystem type, similarly to "df" command on UNIX. If all parameter is False it tries to distinguish and return physical devices only (e.g. hard disks, cd-rom drives, USB keys) and ignore all others (e.g. pseudo, memory, duplicate, inaccessible filesystems). Note that this may not be fully reliable on all systems (e.g. on BSD this parameter is ignored). See disk_usage.py script providing an example usage. Returns a list of namedtuples with the following fields:

• device: the device path (e.g. "/dev/hda1"). On Windows this is the drive letter (e.g. "C:\\").
• mountpoint: the mount point path (e.g. "/"). On Windows this is the drive letter (e.g. "C:\\").
• fstype: the partition filesystem (e.g. "ext3" on UNIX or "NTFS" on Windows).
• opts: a comma-separated string indicating different mount options for the drive/partition. Platform-dependent.
• maxfile: the maximum length a file name can have.
• maxpath: the maximum length a path name (directory name + base file name) can have.

>>> import psutil >>> psutil.disk_partitions() [sdiskpart(device='/dev/sda3', mountpoint='/', fstype='ext4', opts='rw,errors=remount-ro', maxfile=255, maxpath=4096), sdiskpart(device='/dev/sda7', mountpoint='/home', fstype='ext4', opts='rw', maxfile=255, maxpath=4096)]

5.7.4 added maxfile and maxpath fields

disk_usage(path)

Return disk usage statistics about the partition which contains the given path as a named tuple including total, used and free space expressed in bytes, plus the percentage usage. OSError is raised if path does not exist. Starting from Python 3.3 this is also available as shutil.disk_usage (see BPO-12442). See disk_usage.py script providing an example usage.

>>> import psutil >>> psutil.disk_usage('/') sdiskusage(total=21378641920, used=4809781248, free=15482871808, percent=22.5)

Note

UNIX usually reserves 5% of the total disk space for the root user. total and used fields on UNIX refer to the overall total and used space, whereas free represents the space available for the user and percent represents the user utilization (see source code). That is why percent value may look 5% bigger than what you would expect it to be. Also note that both 4 values match "df" cmdline utility.

4.3.0 percent value takes root reserved space into account.

disk_io_counters(perdisk=False, nowrap=True)

Return system-wide disk I/O statistics as a named tuple including the following fields:

• read_count: number of reads
• write_count: number of writes
• read_bytes: number of bytes read
• write_bytes: number of bytes written

Platform-specific fields:

• read_time: (all except NetBSD and OpenBSD) time spent reading from disk (in milliseconds)
• write_time: (all except NetBSD and OpenBSD) time spent writing to disk (in milliseconds)
• busy_time: (Linux, FreeBSD) time spent doing actual I/Os (in milliseconds)
• read_merged_count (Linux): number of merged reads (see iostats doc)
• write_merged_count (Linux): number of merged writes (see iostats doc)

If perdisk is True return the same information for every physical disk installed on the system as a dictionary with partition names as the keys and the named tuple described above as the values. See iotop.py for an example application. On some systems such as Linux, on a very busy or long-lived system, the numbers returned by the kernel may overflow and wrap (restart from zero). If nowrap is True psutil will detect and adjust those numbers across function calls and add "old value" to "new value" so that the returned numbers will always be increasing or remain the same, but never decrease. disk_io_counters.cache_clear() can be used to invalidate the nowrap cache. On Windows it may be ncessary to issue diskperf -y command from cmd.exe first in order to enable IO counters. On diskless machines this function will return None or {} if perdisk is True.

>>> import psutil >>> psutil.disk_io_counters() sdiskio(read_count=8141, write_count=2431, read_bytes=290203, write_bytes=537676, read_time=5868, write_time=94922) >>> >>> psutil.disk_io_counters(perdisk=True) {'sda1': sdiskio(read_count=920, write_count=1, read_bytes=2933248, write_bytes=512, read_time=6016, write_time=4), 'sda2': sdiskio(read_count=18707, write_count=8830, read_bytes=6060, write_bytes=3443, read_time=24585, write_time=1572), 'sdb1': sdiskio(read_count=161, write_count=0, read_bytes=786432, write_bytes=0, read_time=44, write_time=0)}

Note

on Windows "diskperf -y" command may need to be executed first otherwise this function won't find any disk.

5.3.0 numbers no longer wrap (restart from zero) across calls thanks to new nowrap argument.

4.0.0 added busy_time (Linux, FreeBSD), read_merged_count and write_merged_count (Linux) fields.

4.0.0 NetBSD no longer has read_time and write_time fields.

Network

net_io_counters(pernic=False, nowrap=True)

Return system-wide network I/O statistics as a named tuple including the following attributes:

• bytes_sent: number of bytes sent
• bytes_recv: number of bytes received
• packets_sent: number of packets sent
• packets_recv: number of packets received
• errin: total number of errors while receiving
• errout: total number of errors while sending
• dropin: total number of incoming packets which were dropped
• dropout: total number of outgoing packets which were dropped (always 0 on macOS and BSD)

If pernic is True return the same information for every network interface installed on the system as a dictionary with network interface names as the keys and the named tuple described above as the values. On some systems such as Linux, on a very busy or long-lived system, the numbers returned by the kernel may overflow and wrap (restart from zero). If nowrap is True psutil will detect and adjust those numbers across function calls and add "old value" to "new value" so that the returned numbers will always be increasing or remain the same, but never decrease. net_io_counters.cache_clear() can be used to invalidate the nowrap cache. On machines with no network iterfaces this function will return None or {} if pernic is True.

>>> import psutil >>> psutil.net_io_counters() snetio(bytes_sent=14508483, bytes_recv=62749361, packets_sent=84311, packets_recv=94888, errin=0, errout=0, dropin=0, dropout=0) >>> >>> psutil.net_io_counters(pernic=True) {'lo': snetio(bytes_sent=547971, bytes_recv=547971, packets_sent=5075, packets_recv=5075, errin=0, errout=0, dropin=0, dropout=0), 'wlan0': snetio(bytes_sent=13921765, bytes_recv=62162574, packets_sent=79097, packets_recv=89648, errin=0, errout=0, dropin=0, dropout=0)}

Also see nettop.py and ifconfig.py for an example application.

5.3.0 numbers no longer wrap (restart from zero) across calls thanks to new nowrap argument.

net_connections(kind='inet')

Return system-wide socket connections as a list of named tuples. Every named tuple provides 7 attributes:

• fd: the socket file descriptor. If the connection refers to the current process this may be passed to socket.fromfd to obtain a usable socket object. On Windows and SunOS this is always set to -1.
• family: the address family, either AF_INET, AF_INET6 or AF_UNIX.
• type: the address type, either SOCK_STREAM, SOCK_DGRAM or SOCK_SEQPACKET.
• laddr: the local address as a (ip, port) named tuple or a path in case of AF_UNIX sockets. For UNIX sockets see notes below.
• raddr: the remote address as a (ip, port) named tuple or an absolute path in case of UNIX sockets. When the remote endpoint is not connected you'll get an empty tuple (AF_INET*) or "" (AF_UNIX). For UNIX sockets see notes below.
• status: represents the status of a TCP connection. The return value is one of the psutil.CONN_* constants (a string). For UDP and UNIX sockets this is always going to be psutil.CONN_NONE.
• pid: the PID of the process which opened the socket, if retrievable, else None. On some platforms (e.g. Linux) the availability of this field changes depending on process privileges (root is needed).

The kind parameter is a string which filters for connections matching the following criteria:

Kind value	Connections using
"inet"	IPv4 and IPv6
"inet4"	IPv4
"inet6"	IPv6
"tcp"	TCP
"tcp4"	TCP over IPv4
"tcp6"	TCP over IPv6
"udp"	UDP
"udp4"	UDP over IPv4
"udp6"	UDP over IPv6
"unix"	UNIX socket (both UDP and TCP protocols)
"all"	the sum of all the possible families and protocols

On macOS and AIX this function requires root privileges. To get per-process connections use Process.connections. Also, see netstat.py example script. Example:

>>> import psutil >>> psutil.net_connections() [pconn(fd=115, family=<AddressFamily.AF_INET: 2>, type=<SocketType.SOCK_STREAM: 1>, laddr=addr(ip='10.0.0.1', port=48776), raddr=addr(ip='93.186.135.91', port=80), status='ESTABLISHED', pid=1254), pconn(fd=117, family=<AddressFamily.AF_INET: 2>, type=<SocketType.SOCK_STREAM: 1>, laddr=addr(ip='10.0.0.1', port=43761), raddr=addr(ip='72.14.234.100', port=80), status='CLOSING', pid=2987), pconn(fd=-1, family=<AddressFamily.AF_INET: 2>, type=<SocketType.SOCK_STREAM: 1>, laddr=addr(ip='10.0.0.1', port=60759), raddr=addr(ip='72.14.234.104', port=80), status='ESTABLISHED', pid=None), pconn(fd=-1, family=<AddressFamily.AF_INET: 2>, type=<SocketType.SOCK_STREAM: 1>, laddr=addr(ip='10.0.0.1', port=51314), raddr=addr(ip='72.14.234.83', port=443), status='SYN_SENT', pid=None) ...]

Note

(macOS and AIX) psutil.AccessDenied is always raised unless running as root. This is a limitation of the OS and lsof does the same.

Note

(Solaris) UNIX sockets are not supported.

Note

(Linux, FreeBSD) "raddr" field for UNIX sockets is always set to "". This is a limitation of the OS.

Note

(OpenBSD) "laddr" and "raddr" fields for UNIX sockets are always set to "". This is a limitation of the OS.

2.1.0

5.3.0 : socket "fd" is now set for real instead of being -1.

5.3.0 : "laddr" and "raddr" are named tuples.

net_if_addrs()

Return the addresses associated to each NIC (network interface card) installed on the system as a dictionary whose keys are the NIC names and value is a list of named tuples for each address assigned to the NIC. Each named tuple includes 5 fields:

• family: the address family, either AF_INET or AF_INET6 or psutil.AF_LINK, which refers to a MAC address.
• address: the primary NIC address (always set).
• netmask: the netmask address (may be None).
• broadcast: the broadcast address (may be None).
• ptp: stands for "point to point"; it's the destination address on a point to point interface (typically a VPN). broadcast and ptp are mutually exclusive. May be None.

Example:

>>> import psutil
>>> psutil.net_if_addrs()
{'lo': [snicaddr(family=<AddressFamily.AF_INET: 2>, address='127.0.0.1', netmask='255.0.0.0', broadcast='127.0.0.1', ptp=None),
        snicaddr(family=<AddressFamily.AF_INET6: 10>, address='::1', netmask='ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff', broadcast=None, ptp=None),
        snicaddr(family=<AddressFamily.AF_LINK: 17>, address='00:00:00:00:00:00', netmask=None, broadcast='00:00:00:00:00:00', ptp=None)],
 'wlan0': [snicaddr(family=<AddressFamily.AF_INET: 2>, address='192.168.1.3', netmask='255.255.255.0', broadcast='192.168.1.255', ptp=None),
           snicaddr(family=<AddressFamily.AF_INET6: 10>, address='fe80::c685:8ff:fe45:641%wlan0', netmask='ffff:ffff:ffff:ffff::', broadcast=None, ptp=None),
           snicaddr(family=<AddressFamily.AF_LINK: 17>, address='c4:85:08:45:06:41', netmask=None, broadcast='ff:ff:ff:ff:ff:ff', ptp=None)]}
>>>

See also nettop.py and ifconfig.py for an example application.

Note

if you're interested in others families (e.g. AF_BLUETOOTH) you can use the more powerful netifaces extension.

Note

you can have more than one address of the same family associated with each interface (that's why dict values are lists).

Note

broadcast and ptp are not supported on Windows and are always None.

3.0.0

3.2.0 ptp field was added.

4.4.0 added support for netmask field on Windows which is no longer None.

net_if_stats()

Return information about each NIC (network interface card) installed on the system as a dictionary whose keys are the NIC names and value is a named tuple with the following fields:

• isup: a bool indicating whether the NIC is up and running (meaning ethernet cable or Wi-Fi is connected).
• duplex: the duplex communication type; it can be either NIC_DUPLEX_FULL, NIC_DUPLEX_HALF or NIC_DUPLEX_UNKNOWN.
• speed: the NIC speed expressed in mega bits (MB), if it can't be determined (e.g. 'localhost') it will be set to 0.
• mtu: NIC's maximum transmission unit expressed in bytes.

Example:

>>> import psutil >>> psutil.net_if_stats() {'eth0': snicstats(isup=True, duplex=<NicDuplex.NIC_DUPLEX_FULL: 2>, speed=100, mtu=1500), 'lo': snicstats(isup=True, duplex=<NicDuplex.NIC_DUPLEX_UNKNOWN: 0>, speed=0, mtu=65536)}

Also see nettop.py and ifconfig.py for an example application.

3.0.0

5.7.3 isup on UNIX also checks whether the NIC is running.

Sensors

sensors_temperatures(fahrenheit=False)

Return hardware temperatures. Each entry is a named tuple representing a certain hardware temperature sensor (it may be a CPU, an hard disk or something else, depending on the OS and its configuration). All temperatures are expressed in celsius unless fahrenheit is set to True. If sensors are not supported by the OS an empty dict is returned. Example:

>>> import psutil
>>> psutil.sensors_temperatures()
{'acpitz': [shwtemp(label='', current=47.0, high=103.0, critical=103.0)],
 'asus': [shwtemp(label='', current=47.0, high=None, critical=None)],
 'coretemp': [shwtemp(label='Physical id 0', current=52.0, high=100.0, critical=100.0),
              shwtemp(label='Core 0', current=45.0, high=100.0, critical=100.0),
              shwtemp(label='Core 1', current=52.0, high=100.0, critical=100.0),
              shwtemp(label='Core 2', current=45.0, high=100.0, critical=100.0),
              shwtemp(label='Core 3', current=47.0, high=100.0, critical=100.0)]}

See also temperatures.py and sensors.py for an example application.

Availability: Linux, FreeBSD

5.1.0

5.5.0 added FreeBSD support

sensors_fans()

Return hardware fans speed. Each entry is a named tuple representing a certain hardware sensor fan. Fan speed is expressed in RPM (revolutions per minute). If sensors are not supported by the OS an empty dict is returned. Example:

>>> import psutil
>>> psutil.sensors_fans()
{'asus': [sfan(label='cpu_fan', current=3200)]}

See also fans.py and sensors.py for an example application.

Availability: Linux

5.2.0

sensors_battery()

Return battery status information as a named tuple including the following values. If no battery is installed or metrics can't be determined None is returned.

• percent: battery power left as a percentage.
• secsleft: a rough approximation of how many seconds are left before the battery runs out of power. If the AC power cable is connected this is set to psutil.POWER_TIME_UNLIMITED <psutil.POWER_TIME_UNLIMITED>. If it can't be determined it is set to psutil.POWER_TIME_UNKNOWN <psutil.POWER_TIME_UNKNOWN>.
• power_plugged: True if the AC power cable is connected, False if not or None if it can't be determined.

Example:

>>> import psutil
>>>
>>> def secs2hours(secs):
...     mm, ss = divmod(secs, 60)
...     hh, mm = divmod(mm, 60)
...     return "%d:%02d:%02d" % (hh, mm, ss)
...
>>> battery = psutil.sensors_battery()
>>> battery
sbattery(percent=93, secsleft=16628, power_plugged=False)
>>> print("charge = %s%%, time left = %s" % (battery.percent, secs2hours(battery.secsleft)))
charge = 93%, time left = 4:37:08

See also battery.py and sensors.py for an example application.

Availability: Linux, Windows, FreeBSD

5.1.0

5.4.2 added macOS support

Other system info

boot_time()

Return the system boot time expressed in seconds since the epoch. Example:

>>> import psutil, datetime
>>> psutil.boot_time()
1389563460.0
>>> datetime.datetime.fromtimestamp(psutil.boot_time()).strftime("%Y-%m-%d %H:%M:%S")
'2014-01-12 22:51:00'

Note

on Windows this function may return a time which is off by 1 second if it's used across different processes (see issue #1007).

users()

Return users currently connected on the system as a list of named tuples including the following fields:

• name: the name of the user.
• terminal: the tty or pseudo-tty associated with the user, if any, else None.
• host: the host name associated with the entry, if any.
• started: the creation time as a floating point number expressed in seconds since the epoch.
• pid: the PID of the login process (like sshd, tmux, gdm-session-worker, ...). On Windows and OpenBSD this is always set to None.

Example:

>>> import psutil
>>> psutil.users()
[suser(name='giampaolo', terminal='pts/2', host='localhost', started=1340737536.0, pid=1352),
 suser(name='giampaolo', terminal='pts/3', host='localhost', started=1340737792.0, pid=1788)]

5.3.0 added "pid" field

Processes

Functions

pids()

Return a sorted list of current running PIDs. To iterate over all processes and avoid race conditions process_iter() should be preferred.

>>> import psutil >>> psutil.pids() [1, 2, 3, 5, 7, 8, 9, 10, 11, 12, 13, 14, 15, 17, 18, 19, ..., 32498]

5.6.0 PIDs are returned in sorted order

process_iter(attrs=None, ad_value=None)

Return an iterator yielding a Process class instance for all running processes on the local machine. This should be preferred over psutil.pids() to iterate over processes as it's safe from race condition.

Every Process instance is only created once, and then cached for the next time psutil.process_iter() is called (if PID is still alive). Also it makes sure process PIDs are not reused.

attrs and ad_value have the same meaning as in Process.as_dict(). If attrs is specified Process.as_dict() result will be stored as a info attribute attached to the returned Process instances. If attrs is an empty list it will retrieve all process info (slow).

Sorting order in which processes are returned is based on their PID.

Example:

>>> import psutil
>>> for proc in psutil.process_iter(['pid', 'name', 'username']):
...     print(proc.info)
...
{'name': 'systemd', 'pid': 1, 'username': 'root'}
{'name': 'kthreadd', 'pid': 2, 'username': 'root'}
{'name': 'ksoftirqd/0', 'pid': 3, 'username': 'root'}
...

A dict comprehensions to create a {pid: info, ...} data structure:

>>> import psutil
>>> procs = {p.pid: p.info for p in psutil.process_iter(['name', 'username'])}
>>> procs
{1: {'name': 'systemd', 'username': 'root'},
 2: {'name': 'kthreadd', 'username': 'root'},
 3: {'name': 'ksoftirqd/0', 'username': 'root'},
 ...}

5.3.0 added "attrs" and "ad_value" parameters.

pid_exists(pid)

Check whether the given PID exists in the current process list. This is faster than doing pid in psutil.pids() and should be preferred.

wait_procs(procs, timeout=None, callback=None)

Convenience function which waits for a list of Process instances to terminate. Return a (gone, alive) tuple indicating which processes are gone and which ones are still alive. The gone ones will have a new returncode attribute indicating process exit status as returned by Process.wait. callback is a function which gets called when one of the processes being waited on is terminated and a Process instance is passed as callback argument (the instance will also have a returncode attribute set). This function will return as soon as all processes terminate or when timeout (seconds) occurs. Differently from Process.wait it will not raise TimeoutExpired if timeout occurs. A typical use case may be:

• send SIGTERM to a list of processes
• give them some time to terminate
• send SIGKILL to those ones which are still alive

Example which terminates and waits all the children of this process:

import psutil

def on_terminate(proc):
    print("process {} terminated with exit code {}".format(proc, proc.returncode))

procs = psutil.Process().children()
for p in procs:
    p.terminate()
gone, alive = psutil.wait_procs(procs, timeout=3, callback=on_terminate)
for p in alive:
    p.kill()

Exceptions

Base exception class. All other exceptions inherit from this one.

Raised by Process class methods when no process with the given pid is found in the current process list or when a process no longer exists. name is the name the process had before disappearing and gets set only if Process.name() was previously called.

This may be raised by Process class methods when querying a zombie process on UNIX (Windows doesn't have zombie processes). Depending on the method called the OS may be able to succeed in retrieving the process information or not. Note: this is a subclass of NoSuchProcess so if you're not interested in retrieving zombies (e.g. when using process_iter()) you can ignore this exception and just catch NoSuchProcess.

3.0.0

Raised by Process class methods when permission to perform an action is denied. "name" is the name of the process (may be None).

Raised by Process.wait if timeout expires and process is still alive.

Process class

Represents an OS process with the given pid. If pid is omitted current process pid (os.getpid) is used. Raise NoSuchProcess if pid does not exist. On Linux pid can also refer to a thread ID (the id field returned by threads method). When accessing methods of this class always be prepared to catch NoSuchProcess and AccessDenied exceptions. hash builtin can be used against instances of this class in order to identify a process univocally over time (the hash is determined by mixing process PID + creation time). As such it can also be used with set.

Note

In order to efficiently fetch more than one information about the process at the same time, make sure to use either oneshot context manager or as_dict utility method.

Note

the way this class is bound to a process is uniquely via its PID. That means that if the process terminates and the OS reuses its PID you may end up interacting with another process. The only exceptions for which process identity is preemptively checked (via PID + creation time) is for the following methods: nice (set), ionice (set), cpu_affinity (set), rlimit (set), children, parent, parents, suspend resume, send_signal, terminate kill. To prevent this problem for all other methods you can use is_running() before querying the process or process_iter() in case you're iterating over all processes. It must be noted though that unless you deal with very "old" (inactive) Process instances this will hardly represent a problem.

oneshot()

Utility context manager which considerably speeds up the retrieval of multiple process information at the same time. Internally different process info (e.g. name, ppid, uids, create_time, ...) may be fetched by using the same routine, but only one value is returned and the others are discarded. When using this context manager the internal routine is executed once (in the example below on name()) the value of interest is returned and the others are cached. The subsequent calls sharing the same internal routine will return the cached value. The cache is cleared when exiting the context manager block. The advice is to use this every time you retrieve more than one information about the process. If you're lucky, you'll get a hell of a speedup. Example:

>>> import psutil >>> p = psutil.Process() >>> with p.oneshot(): ... p.name() # execute internal routine once collecting multiple info ... p.cpu_times() # return cached value ... p.cpu_percent() # return cached value ... p.create_time() # return cached value ... p.ppid() # return cached value ... p.status() # return cached value ... >>>

Here's a list of methods which can take advantage of the speedup depending on what platform you're on. In the table below horizontal emtpy rows indicate what process methods can be efficiently grouped together internally. The last column (speedup) shows an approximation of the speedup you can get if you call all the methods together (best case scenario).

Linux	Windows	macOS	BSD	SunOS	AIX
cpu_num	~Process.cpu_percent	~Process.cpu_percent	cpu_num	name	name
~Process.cpu_percent	cpu_times	cpu_times	~Process.cpu_percent	cmdline	cmdline
cpu_times	io_counters()	memory_info	cpu_times	create_time	create_time
create_time	memory_info	memory_percent	create_time
name	memory_maps	num_ctx_switches	gids	memory_info	memory_info
ppid	num_ctx_switches	num_threads	io_counters	memory_percent	memory_percent
status	num_handles		name	num_threads	num_threads
terminal	num_threads	create_time	memory_info	ppid	ppid
	username	gids	memory_percent	status	status
gids		name	num_ctx_switches	terminal	terminal
num_ctx_switches	exe	ppid	ppid
num_threads	name	status	status	gids	gids
uids		terminal	terminal	uids	uids
username		uids	uids	username	username
		username	username
memory_full_info
memory_maps
speedup: +2.6x	speedup: +1.8x / +6.5x	speedup: +1.9x	speedup: +2.0x	speedup: +1.3x	speedup: +1.3x

5.0.0

pid

The process PID. This is the only (read-only) attribute of the class.

ppid()

The process parent PID. On Windows the return value is cached after first call. Not on POSIX because ppid may change if process becomes a zombie See also parent and parents methods.

name()

The process name. On Windows the return value is cached after first call. Not on POSIX because the process name may change. See also how to find a process by name.

exe()

The process executable as an absolute path. On some systems this may also be an empty string. The return value is cached after first call.

>>> import psutil >>> psutil.Process().exe() '/usr/bin/python2.7'

cmdline()

The command line this process has been called with as a list of strings. The return value is not cached because the cmdline of a process may change.

>>> import psutil >>> psutil.Process().cmdline() ['python', 'manage.py', 'runserver']

environ()

The environment variables of the process as a dict. Note: this might not reflect changes made after the process started.

>>> import psutil >>> psutil.Process().environ() {'LC_NUMERIC': 'it_IT.UTF-8', 'QT_QPA_PLATFORMTHEME': 'appmenu-qt5', 'IM_CONFIG_PHASE': '1', 'XDG_GREETER_DATA_DIR': '/var/lib/lightdm-data/giampaolo', 'GNOME_DESKTOP_SESSION_ID': 'this-is-deprecated', 'XDG_CURRENT_DESKTOP': 'Unity', 'UPSTART_EVENTS': 'started starting', 'GNOME_KEYRING_PID': '', 'XDG_VTNR': '7', 'QT_IM_MODULE': 'ibus', 'LOGNAME': 'giampaolo', 'USER': 'giampaolo', 'PATH': '/home/giampaolo/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/home/giampaolo/svn/sysconf/bin', 'LC_PAPER': 'it_IT.UTF-8', 'GNOME_KEYRING_CONTROL': '', 'GTK_IM_MODULE': 'ibus', 'DISPLAY': ':0', 'LANG': 'en_US.UTF-8', 'LESS_TERMCAP_se': 'x1b[0m', 'TERM': 'xterm-256color', 'SHELL': '/bin/bash', 'XDG_SESSION_PATH': '/org/freedesktop/DisplayManager/Session0', 'XAUTHORITY': '/home/giampaolo/.Xauthority', 'LANGUAGE': 'en_US', 'COMPIZ_CONFIG_PROFILE': 'ubuntu', 'LC_MONETARY': 'it_IT.UTF-8', 'QT_LINUX_ACCESSIBILITY_ALWAYS_ON': '1', 'LESS_TERMCAP_me': 'x1b[0m', 'LESS_TERMCAP_md': 'x1b[01;38;5;74m', 'LESS_TERMCAP_mb': 'x1b[01;31m', 'HISTSIZE': '100000', 'UPSTART_INSTANCE': '', 'CLUTTER_IM_MODULE': 'xim', 'WINDOWID': '58786407', 'EDITOR': 'vim', 'SESSIONTYPE': 'gnome-session', 'XMODIFIERS': '@im=ibus', 'GPG_AGENT_INFO': '/home/giampaolo/.gnupg/S.gpg-agent:0:1', 'HOME': '/home/giampaolo', 'HISTFILESIZE': '100000', 'QT4_IM_MODULE': 'xim', 'GTK2_MODULES': 'overlay-scrollbar', 'XDG_SESSION_DESKTOP': 'ubuntu', 'SHLVL': '1', 'XDG_RUNTIME_DIR': '/run/user/1000', 'INSTANCE': 'Unity', 'LC_ADDRESS': 'it_IT.UTF-8', 'SSH_AUTH_SOCK': '/run/user/1000/keyring/ssh', 'VTE_VERSION': '4205', 'GDMSESSION': 'ubuntu', 'MANDATORY_PATH': '/usr/share/gconf/ubuntu.mandatory.path', 'VISUAL': 'vim', 'DESKTOP_SESSION': 'ubuntu', 'QT_ACCESSIBILITY': '1', 'XDG_SEAT_PATH': '/org/freedesktop/DisplayManager/Seat0', 'LESSCLOSE': '/usr/bin/lesspipe %s %s', 'LESSOPEN': '| /usr/bin/lesspipe %s', 'XDG_SESSION_ID': 'c2', 'DBUS_SESSION_BUS_ADDRESS': 'unix:abstract=/tmp/dbus-9GAJpvnt8r', '_': '/usr/bin/python', 'DEFAULTS_PATH': '/usr/share/gconf/ubuntu.default.path', 'LC_IDENTIFICATION': 'it_IT.UTF-8', 'LESS_TERMCAP_ue': 'x1b[0m', 'UPSTART_SESSION': 'unix:abstract=/com/ubuntu/upstart-session/1000/1294', 'XDG_CONFIG_DIRS': '/etc/xdg/xdg-ubuntu:/usr/share/upstart/xdg:/etc/xdg', 'GTK_MODULES': 'gail:atk-bridge:unity-gtk-module', 'XDG_SESSION_TYPE': 'x11', 'PYTHONSTARTUP': '/home/giampaolo/.pythonstart', 'LC_NAME': 'it_IT.UTF-8', 'OLDPWD': '/home/giampaolo/svn/curio_giampaolo/tests', 'GDM_LANG': 'en_US', 'LC_TELEPHONE': 'it_IT.UTF-8', 'HISTCONTROL': 'ignoredups:erasedups', 'LC_MEASUREMENT': 'it_IT.UTF-8', 'PWD': '/home/giampaolo/svn/curio_giampaolo', 'JOB': 'gnome-session', 'LESS_TERMCAP_us': 'x1b[04;38;5;146m', 'UPSTART_JOB': 'unity-settings-daemon', 'LC_TIME': 'it_IT.UTF-8', 'LESS_TERMCAP_so': 'x1b[38;5;246m', 'PAGER': 'less', 'XDG_DATA_DIRS': '/usr/share/ubuntu:/usr/share/gnome:/usr/local/share/:/usr/share/:/var/lib/snapd/desktop', 'XDG_SEAT': 'seat0'}

4.0.0

5.3.0 added SunOS support

5.6.3 added AIX suport

5.7.3 added BSD suport

create_time()

The process creation time as a floating point number expressed in seconds since the epoch. The return value is cached after first call.

>>> import psutil, datetime >>> p = psutil.Process() >>> p.create_time() 1307289803.47 >>> datetime.datetime.fromtimestamp(p.create_time()).strftime("%Y-%m-%d %H:%M:%S") '2011-03-05 18:03:52'

as_dict(attrs=None, ad_value=None)

Utility method retrieving multiple process information as a dictionary. If attrs is specified it must be a list of strings reflecting available Process class's attribute names. Here's a list of possible string values: 'cmdline', 'connections', 'cpu_affinity', 'cpu_num', 'cpu_percent', 'cpu_times', 'create_time', 'cwd', 'environ', 'exe', 'gids', 'io_counters', 'ionice', 'memory_full_info', 'memory_info', 'memory_maps', 'memory_percent', 'name', 'nice', 'num_ctx_switches', 'num_fds', 'num_handles', 'num_threads', 'open_files', 'pid', 'ppid', 'status', 'terminal', 'threads', 'uids', 'username'. If *attrs* argument is not passed all public read only attributes are assumed. *ad_value* is the value which gets assigned to a dict key in case :class:`AccessDenied or ZombieProcess exception is raised when retrieving that particular process information. Internally, as_dict uses oneshot context manager so there's no need you use it also.

>>> import psutil >>> p = psutil.Process() >>> p.as_dict(attrs=['pid', 'name', 'username']) {'username': 'giampaolo', 'pid': 12366, 'name': 'python'} >>> >>> # get a list of valid attrs names >>> list(psutil.Process().as_dict().keys()) ['status', 'cpu_num', 'num_ctx_switches', 'pid', 'memory_full_info', 'connections', 'cmdline', 'create_time', 'ionice', 'num_fds', 'memory_maps', 'cpu_percent', 'terminal', 'ppid', 'cwd', 'nice', 'username', 'cpu_times', 'io_counters', 'memory_info', 'threads', 'open_files', 'name', 'num_threads', 'exe', 'uids', 'gids', 'cpu_affinity', 'memory_percent', 'environ']

3.0.0 ad_value is used also when incurring into ZombieProcess exception, not only AccessDenied

4.5.0 as_dict is considerably faster thanks to oneshot context manager.

parent()

Utility method which returns the parent process as a Process object, preemptively checking whether PID has been reused. If no parent PID is known return None. See also ppid and parents methods.

parents()

Utility method which return the parents of this process as a list of Process instances. If no parents are known return an empty list. See also ppid and parent methods.

5.6.0

status()

The current process status as a string. The returned string is one of the psutil.STATUS_* constants.

cwd()

The process current working directory as an absolute path.

5.6.4 added support for NetBSD

username()

The name of the user that owns the process. On UNIX this is calculated by using real process uid.

uids()

The real, effective and saved user ids of this process as a named tuple. This is the same as os.getresuid but can be used for any process PID.

Availability: UNIX

gids()

The real, effective and saved group ids of this process as a named tuple. This is the same as os.getresgid but can be used for any process PID.

Availability: UNIX

terminal()

The terminal associated with this process, if any, else None. This is similar to "tty" command but can be used for any process PID.

Availability: UNIX

nice(value=None)

Get or set process niceness (priority). On UNIX this is a number which usually goes from -20 to 20. The higher the nice value, the lower the priority of the process.

>>> import psutil >>> p = psutil.Process() >>> p.nice(10) # set >>> p.nice() # get 10 >>>

Starting from Python 3.3 this functionality is also available as os.getpriority and os.setpriority (see BPO-10784). On Windows this is implemented via GetPriorityClass and SetPriorityClass Windows APIs and value is one of the psutil.*_PRIORITY_CLASS <psutil.ABOVE_NORMAL_PRIORITY_CLASS> constants reflecting the MSDN documentation. Example which increases process priority on Windows:

>>> p.nice(psutil.HIGH_PRIORITY_CLASS)

ionice(ioclass=None, value=None)

Get or set process I/O niceness (priority). If no argument is provided it acts as a get, returning a (ioclass, value) tuple on Linux and a ioclass integer on Windows. If ioclass is provided it acts as a set. In this case an additional value can be specified on Linux only in order to increase or decrease the I/O priority even further. Here's the possible platform-dependent ioclass values.

Linux (see ioprio_get manual):

• IOPRIO_CLASS_RT: (high) the process gets first access to the disk every time. Use it with care as it can starve the entire system. Additional priority level can be specified and ranges from 0 (highest) to 7 (lowest).
• IOPRIO_CLASS_BE: (normal) the default for any process that hasn't set a specific I/O priority. Additional priority level ranges from 0 (highest) to 7 (lowest).
• IOPRIO_CLASS_IDLE: (low) get I/O time when no-one else needs the disk. No additional value is accepted.
• IOPRIO_CLASS_NONE: returned when no priority was previously set.

Windows:

• IOPRIO_HIGH: highest priority.
• IOPRIO_NORMAL: default priority.
• IOPRIO_LOW: low priority.
• IOPRIO_VERYLOW: lowest priority.

Here's an example on how to set the highest I/O priority depending on what platform you're on:

>>> import psutil
>>> p = psutil.Process()
>>> if psutil.LINUX:
...     p.ionice(psutil.IOPRIO_CLASS_RT, value=7)
... else:
...     p.ionice(psutil.IOPRIO_HIGH)
...
>>> p.ionice()  # get
pionice(ioclass=<IOPriority.IOPRIO_CLASS_RT: 1>, value=7)

Availability: Linux, Windows Vista+

5.6.2 Windows accepts new IOPRIO_* constants including new IOPRIO_HIGH.

rlimit(resource, limits=None)

Get or set process resource limits (see man prlimit). resource is one of the psutil.RLIMIT_* constants. limits is a (soft, hard) tuple. This is the same as resource.getrlimit and resource.setrlimit but can be used for any process PID, not only os.getpid. For get, return value is a (soft, hard) tuple. Each value may be either and integer or psutil.RLIMIT_* <psutil.RLIM_INFINITY>. Example:

>>> import psutil >>> p = psutil.Process() >>> p.rlimit(psutil.RLIMIT_NOFILE, (128, 128)) # process can open max 128 file descriptors >>> p.rlimit(psutil.RLIMIT_FSIZE, (1024, 1024)) # can create files no bigger than 1024 bytes >>> p.rlimit(psutil.RLIMIT_FSIZE) # get (1024, 1024) >>>

Also see procinfo.py script.

Availability: Linux, FreeBSD

5.7.3 added FreeBSD support

io_counters()

Return process I/O statistics as a named tuple. For Linux you can refer to /proc filesystem documentation.

• read_count: the number of read operations performed (cumulative). This is supposed to count the number of read-related syscalls such as read() and pread() on UNIX.
• write_count: the number of write operations performed (cumulative). This is supposed to count the number of write-related syscalls such as write() and pwrite() on UNIX.
• read_bytes: the number of bytes read (cumulative). Always -1 on BSD.
• write_bytes: the number of bytes written (cumulative). Always -1 on BSD.

Linux specific:

• read_chars (Linux): the amount of bytes which this process passed to read() and pread() syscalls (cumulative). Differently from read_bytes it doesn't care whether or not actual physical disk I/O occurred.
• write_chars (Linux): the amount of bytes which this process passed to write() and pwrite() syscalls (cumulative). Differently from write_bytes it doesn't care whether or not actual physical disk I/O occurred.

Windows specific:

• other_count (Windows): the number of I/O operations performed other than read and write operations.
• other_bytes (Windows): the number of bytes transferred during operations other than read and write operations.

>>> import psutil >>> p = psutil.Process() >>> p.io_counters() pio(read_count=454556, write_count=3456, read_bytes=110592, write_bytes=0, read_chars=769931, write_chars=203)

Availability: Linux, BSD, Windows, AIX

5.2.0 added read_chars and write_chars on Linux; added other_count and other_bytes on Windows.

num_ctx_switches()

The number voluntary and involuntary context switches performed by this process (cumulative).

5.4.1 added AIX support

num_fds()

The number of file descriptors currently opened by this process (non cumulative).

Availability: UNIX

num_handles()

The number of handles currently used by this process (non cumulative).

Availability: Windows

num_threads()

The number of threads currently used by this process (non cumulative).

threads()

Return threads opened by process as a list of named tuples including thread id and thread CPU times (user/system). On OpenBSD this method requires root privileges.

cpu_times()

Return a named tuple representing the accumulated process times, in seconds (see explanation). This is similar to os.times but can be used for any process PID.

• user: time spent in user mode.
• system: time spent in kernel mode.
• children_user: user time of all child processes (always 0 on Windows and macOS).
• children_system: system time of all child processes (always 0 on Windows and macOS).
• iowait: (Linux) time spent waiting for blocking I/O to complete. This value is excluded from user and system times count (because the CPU is not doing any work).

>>> import psutil >>> p = psutil.Process() >>> p.cpu_times() pcputimes(user=0.03, system=0.67, children_user=0.0, children_system=0.0, iowait=0.08) >>> sum(p.cpu_times()[:2]) # cumulative, excluding children and iowait 0.70

4.1.0 return two extra fields: children_user and children_system.

5.6.4 added iowait on Linux.

cpu_percent(interval=None)

Return a float representing the process CPU utilization as a percentage which can also be > 100.0 in case of a process running multiple threads on different CPUs. When interval is > 0.0 compares process times to system CPU times elapsed before and after the interval (blocking). When interval is 0.0 or None compares process times to system CPU times elapsed since last call, returning immediately. That means the first time this is called it will return a meaningless 0.0 value which you are supposed to ignore. In this case is recommended for accuracy that this function be called a second time with at least 0.1 seconds between calls. Example:

>>> import psutil >>> p = psutil.Process() >>> # blocking >>> p.cpu_percent(interval=1) 2.0 >>> # non-blocking (percentage since last call) >>> p.cpu_percent(interval=None) 2.9

Note

the returned value can be > 100.0 in case of a process running multiple threads on different CPU cores.

Note

the returned value is explicitly not split evenly between all available CPUs (differently from psutil.cpu_percent()). This means that a busy loop process running on a system with 2 logical CPUs will be reported as having 100% CPU utilization instead of 50%. This was done in order to be consistent with top UNIX utility and also to make it easier to identify processes hogging CPU resources independently from the number of CPUs. It must be noted that taskmgr.exe on Windows does not behave like this (it would report 50% usage instead). To emulate Windows taskmgr.exe behavior you can do: p.cpu_percent() / psutil.cpu_count().

Warning

the first time this method is called with interval = 0.0 or None it will return a meaningless 0.0 value which you are supposed to ignore.

cpu_affinity(cpus=None)

Get or set process current CPU affinity. CPU affinity consists in telling the OS to run a process on a limited set of CPUs only (on Linux cmdline, taskset command is typically used). If no argument is passed it returns the current CPU affinity as a list of integers. If passed it must be a list of integers specifying the new CPUs affinity. If an empty list is passed all eligible CPUs are assumed (and set). On some systems such as Linux this may not necessarily mean all available logical CPUs as in list(range(psutil.cpu_count()))).

>>> import psutil >>> psutil.cpu_count() 4 >>> p = psutil.Process() >>> # get >>> p.cpu_affinity() [0, 1, 2, 3] >>> # set; from now on, process will run on CPU #0 and #1 only >>> p.cpu_affinity([0, 1]) >>> p.cpu_affinity() [0, 1] >>> # reset affinity against all eligible CPUs >>> p.cpu_affinity([])

Availability: Linux, Windows, FreeBSD

2.2.0 added support for FreeBSD

5.1.0 an empty list can be passed to set affinity against all eligible CPUs.

cpu_num()

Return what CPU this process is currently running on. The returned number should be <= psutil.cpu_count(). On FreeBSD certain kernel process may return -1. It may be used in conjunction with psutil.cpu_percent(percpu=True) to observe the system workload distributed across multiple CPUs as shown by cpu_distribution.py example script.

Availability: Linux, FreeBSD, SunOS

5.1.0

memory_info()

Return a named tuple with variable fields depending on the platform representing memory information about the process. The "portable" fields available on all plaforms are rss and vms. All numbers are expressed in bytes.

Linux	macOS	BSD	Solaris	AIX	Windows
rss	rss	rss	rss	rss	rss (alias for wset)
vms	vms	vms	vms	vms	vms (alias for pagefile)
shared	pfaults	text			num_page_faults
text	pageins	data			peak_wset
lib		stack			wset
data					peak_paged_pool
dirty					paged_pool
					peak_nonpaged_pool
					nonpaged_pool
					pagefile
					peak_pagefile
					private

• rss: aka "Resident Set Size", this is the non-swapped physical memory a process has used. On UNIX it matches "top"'s RES column). On Windows this is an alias for wset field and it matches "Mem Usage" column of taskmgr.exe.
• vms: aka "Virtual Memory Size", this is the total amount of virtual memory used by the process. On UNIX it matches "top"'s VIRT column. On Windows this is an alias for pagefile field and it matches "Mem Usage" "VM Size" column of taskmgr.exe.
• shared: (Linux) memory that could be potentially shared with other processes. This matches "top"'s SHR column).
• text (Linux, BSD): aka TRS (text resident set) the amount of memory devoted to executable code. This matches "top"'s CODE column).
• data (Linux, BSD): aka DRS (data resident set) the amount of physical memory devoted to other than executable code. It matches "top"'s DATA column).
• lib (Linux): the memory used by shared libraries.
• dirty (Linux): the number of dirty pages.
• pfaults (macOS): number of page faults.
• pageins (macOS): number of actual pageins.

For on explanation of Windows fields rely on PROCESS_MEMORY_COUNTERS_EX structure doc. Example on Linux:

>>> import psutil >>> p = psutil.Process() >>> p.memory_info() pmem(rss=15491072, vms=84025344, shared=5206016, text=2555904, lib=0, data=9891840, dirty=0)

4.0.0 multiple fields are returned, not only rss and vms.

memory_info_ex()

Same as memory_info (deprecated).

Warning

deprecated in version 4.0.0; use memory_info instead.

memory_full_info()

This method returns the same information as memory_info, plus, on some platform (Linux, macOS, Windows), also provides additional metrics (USS, PSS and swap). The additional metrics provide a better representation of "effective" process memory consumption (in case of USS) as explained in detail in this blog post. It does so by passing through the whole process address. As such it usually requires higher user privileges than memory_info and is considerably slower. On platforms where extra fields are not implemented this simply returns the same metrics as memory_info.

• uss (Linux, macOS, Windows): aka "Unique Set Size", this is the memory which is unique to a process and which would be freed if the process was terminated right now.
• pss (Linux): aka "Proportional Set Size", is the amount of memory shared with other processes, accounted in a way that the amount is divided evenly between the processes that share it. I.e. if a process has 10 MBs all to itself and 10 MBs shared with another process its PSS will be 15 MBs.
• swap (Linux): amount of memory that has been swapped out to disk.

Note

uss is probably the most representative metric for determining how much memory is actually being used by a process. It represents the amount of memory that would be freed if the process was terminated right now.

Example on Linux:

>>> import psutil >>> p = psutil.Process() >>> p.memory_full_info() pfullmem(rss=10199040, vms=52133888, shared=3887104, text=2867200, lib=0, data=5967872, dirty=0, uss=6545408, pss=6872064, swap=0) >>>

See also procsmem.py for an example application.

4.0.0

memory_percent(memtype="rss")

Compare process memory to total physical system memory and calculate process memory utilization as a percentage. memtype argument is a string that dictates what type of process memory you want to compare against. You can choose between the named tuple field names returned by memory_info and memory_full_info (defaults to "rss").

4.0.0 added memtype parameter.

memory_maps(grouped=True)

Return process's mapped memory regions as a list of named tuples whose fields are variable depending on the platform. This method is useful to obtain a detailed representation of process memory usage as explained here (the most important value is "private" memory). If grouped is True the mapped regions with the same path are grouped together and the different memory fields are summed. If grouped is False each mapped region is shown as a single entity and the named tuple will also include the mapped region's address space (addr) and permission set (perms). See pmap.py for an example application.

Linux	Windows	FreeBSD	Solaris
rss	rss	rss	rss
size		private	anonymous
pss		ref_count	locked
shared_clean		shadow_count
shared_dirty
private_clean
private_dirty
referenced
anonymous
swap

>>> import psutil >>> p = psutil.Process() >>> p.memory_maps() [pmmap_grouped(path='/lib/x8664-linux-gnu/libutil-2.15.so', rss=32768, size=2125824, pss=32768, shared_clean=0, shared_dirty=0, private_clean=20480, private_dirty=12288, referenced=32768, anonymous=12288, swap=0), pmmap_grouped(path='/lib/x8664-linux-gnu/libc-2.15.so', rss=3821568, size=3842048, pss=3821568, shared_clean=0, shared_dirty=0, private_clean=0, private_dirty=3821568, referenced=3575808, anonymous=3821568, swap=0), ...]

Availability: Linux, Windows, FreeBSD, SunOS

5.6.0 removed macOS support because inherently broken (see issue #1291)

children(recursive=False)

Return the children of this process as a list of Process instances. If recursive is True return all the parent descendants. Pseudo code example assuming A == this process: :

A ─┐
   │
   ├─ B (child) ─┐
   │             └─ X (grandchild) ─┐
   │                                └─ Y (great grandchild)
   ├─ C (child)
   └─ D (child)

>>> p.children()
B, C, D
>>> p.children(recursive=True)
B, X, Y, C, D

Note that in the example above if process X disappears process Y won't be returned either as the reference to process A is lost. This concept is well summaried by this unit test. See also how to kill a process tree and terminate my children.

open_files()

Return regular files opened by process as a list of named tuples including the following fields:

• path: the absolute file name.
• fd: the file descriptor number; on Windows this is always -1.

Linux only:

• position (Linux): the file (offset) position.
• mode (Linux): a string indicating how the file was opened, similarly to open builtin mode argument. Possible values are 'r', 'w', 'a', 'r+' and 'a+'. There's no distinction between files opened in binary or text mode ("b" or "t").
• flags (Linux): the flags which were passed to the underlying os.open C call when the file was opened (e.g. os.O_RDONLY, os.O_TRUNC, etc).

>>> import psutil >>> f = open('file.ext', 'w') >>> p = psutil.Process() >>> p.open_files() [popenfile(path='/home/giampaolo/svn/psutil/file.ext', fd=3, position=0, mode='w', flags=32769)]

Warning

on Windows this method is not reliable due to some limitations of the underlying Windows API which may hang when retrieving certain file handles. In order to work around that psutil spawns a thread to determine the file handle name and kills it if it's not responding after 100ms. That implies that this method on Windows is not guaranteed to enumerate all regular file handles (see issue 597). Tools like ProcessHacker has the same limitation.

Warning

on BSD this method can return files with a null path ("") due to a kernel bug, hence it's not reliable (see issue 595).

3.1.0 no longer hangs on Windows.

4.1.0 new position, mode and flags fields on Linux.

connections(kind="inet")

Return socket connections opened by process as a list of named tuples. To get system-wide connections use psutil.net_connections(). Every named tuple provides 6 attributes:

• fd: the socket file descriptor. This can be passed to socket.fromfd to obtain a usable socket object. On Windows, FreeBSD and SunOS this is always set to -1.
• family: the address family, either AF_INET, AF_INET6 or AF_UNIX.
• type: the address type, either SOCK_STREAM, SOCK_DGRAM or SOCK_SEQPACKET. .
• laddr: the local address as a (ip, port) named tuple or a path in case of AF_UNIX sockets. For UNIX sockets see notes below.
• raddr: the remote address as a (ip, port) named tuple or an absolute path in case of UNIX sockets. When the remote endpoint is not connected you'll get an empty tuple (AF_INET*) or "" (AF_UNIX). For UNIX sockets see notes below.
• status: represents the status of a TCP connection. The return value is one of the psutil.CONN_* <psutil.CONN_ESTABLISHED> constants. For UDP and UNIX sockets this is always going to be psutil.CONN_NONE.

The kind parameter is a string which filters for connections that fit the following criteria:

Kind value	Connections using
"inet"	IPv4 and IPv6
"inet4"	IPv4
"inet6"	IPv6
"tcp"	TCP
"tcp4"	TCP over IPv4
"tcp6"	TCP over IPv6
"udp"	UDP
"udp4"	UDP over IPv4
"udp6"	UDP over IPv6
"unix"	UNIX socket (both UDP and TCP protocols)
"all"	the sum of all the possible families and protocols

Example:

>>> import psutil >>> p = psutil.Process(1694) >>> p.name() 'firefox' >>> p.connections() [pconn(fd=115, family=<AddressFamily.AF_INET: 2>, type=<SocketType.SOCK_STREAM: 1>, laddr=addr(ip='10.0.0.1', port=48776), raddr=addr(ip='93.186.135.91', port=80), status='ESTABLISHED'), pconn(fd=117, family=<AddressFamily.AF_INET: 2>, type=<SocketType.SOCK_STREAM: 1>, laddr=addr(ip='10.0.0.1', port=43761), raddr=addr(ip='72.14.234.100', port=80), status='CLOSING'), pconn(fd=119, family=<AddressFamily.AF_INET: 2>, type=<SocketType.SOCK_STREAM: 1>, laddr=addr(ip='10.0.0.1', port=60759), raddr=addr(ip='72.14.234.104', port=80), status='ESTABLISHED'), pconn(fd=123, family=<AddressFamily.AF_INET: 2>, type=<SocketType.SOCK_STREAM: 1>, laddr=addr(ip='10.0.0.1', port=51314), raddr=addr(ip='72.14.234.83', port=443), status='SYN_SENT')]

Note

(Solaris) UNIX sockets are not supported.

Note

(Linux, FreeBSD) "raddr" field for UNIX sockets is always set to "". This is a limitation of the OS.

Note

(OpenBSD) "laddr" and "raddr" fields for UNIX sockets are always set to "". This is a limitation of the OS.

Note

(AIX) psutil.AccessDenied is always raised unless running as root (lsof does the same).

5.3.0 : "laddr" and "raddr" are named tuples.

is_running()

Return whether the current process is running in the current process list. This is reliable also in case the process is gone and its PID reused by another process, therefore it must be preferred over doing psutil.pid_exists(p.pid).

Note

this will return True also if the process is a zombie (p.status() == psutil.STATUS_ZOMBIE).

send_signal(signal)

Send a signal to process (see signal module constants) preemptively checking whether PID has been reused. On UNIX this is the same as os.kill(pid, sig). On Windows only SIGTERM, CTRL_C_EVENT and CTRL_BREAK_EVENT signals are supported and SIGTERM is treated as an alias for kill(). See also how to kill a process tree and terminate my children.

3.2.0 support for CTRL_C_EVENT and CTRL_BREAK_EVENT signals on Windows was added.

suspend()

Suspend process execution with SIGSTOP signal preemptively checking whether PID has been reused. On UNIX this is the same as os.kill(pid, signal.SIGSTOP). On Windows this is done by suspending all process threads execution.

resume()

Resume process execution with SIGCONT signal preemptively checking whether PID has been reused. On UNIX this is the same as os.kill(pid, signal.SIGCONT). On Windows this is done by resuming all process threads execution.

terminate()

Terminate the process with SIGTERM signal preemptively checking whether PID has been reused. On UNIX this is the same as os.kill(pid, signal.SIGTERM). On Windows this is an alias for kill. See also how to kill a process tree and terminate my children.

kill()

Kill the current process by using SIGKILL signal preemptively checking whether PID has been reused. On UNIX this is the same as os.kill(pid, signal.SIGKILL). On Windows this is done by using TerminateProcess. See also how to kill a process tree and terminate my children.

wait(timeout=None)

Wait for a process PID to terminate. The details about the return value differ on UNIX and Windows.

On UNIX: if the process terminated normally, the return value is a positive integer >= 0 indicating the exit code. If the process was terminated by a signal return the negated value of the signal which caused the termination (e.g. -SIGTERM). If PID is not a children of os.getpid (current process) just wait until the process disappears and return None. If PID does not exist return None immediately.

On Windows: always return the exit code, which is a positive integer as returned by GetExitCodeProcess.

timeout is expressed in seconds. If specified and the process is still alive raise TimeoutExpired exception. timeout=0 can be used in non-blocking apps: it will either return immediately or raise TimeoutExpired.

The return value is cached. To wait for multiple processes use psutil.wait_procs().

>>> import psutil >>> p = psutil.Process(9891) >>> p.terminate() >>> p.wait() <Negsignal.SIGTERM: -15>

5.7.1 return value is cached (instead of returning None).

5.7.1 on POSIX, in case of negative signal, return it as a human readable enum.

Same as subprocess.Popen but in addition it provides all psutil.Process methods in a single class. For the following methods which are common to both classes, psutil implementation takes precedence: send_signal() <psutil.Process.send_signal()>, terminate() <psutil.Process.terminate()>, kill() <psutil.Process.kill()>. This is done in order to avoid killing another process in case its PID has been reused, fixing BPO-6973.

>>> import psutil >>> from subprocess import PIPE >>> >>> p = psutil.Popen(["/usr/bin/python", "-c", "print('hello')"], stdout=PIPE) >>> p.name() 'python' >>> p.username() 'giampaolo' >>> p.communicate() ('hellon', None) >>> p.wait(timeout=2) 0 >>>

4.4.0 added context manager support

Windows services

win_service_iter()

Return an iterator yielding a WindowsService class instance for all Windows services installed.

4.2.0

Availability: Windows

win_service_get(name)

Get a Windows service by name, returning a WindowsService instance. Raise psutil.NoSuchProcess if no service with such name exists.

4.2.0

Availability: Windows

Represents a Windows service with the given name. This class is returned by win_service_iter and win_service_get functions and it is not supposed to be instantiated directly.

name()

The service name. This string is how a service is referenced and can be passed to win_service_get to get a new WindowsService instance.

display_name()

The service display name. The value is cached when this class is instantiated.

binpath()

The fully qualified path to the service binary/exe file as a string, including command line arguments.

username()

The name of the user that owns this service.

start_type()

A string which can either be "automatic", "manual" or "disabled".

pid()

The process PID, if any, else None. This can be passed to Process class to control the service's process.

status()

Service status as a string, which may be either "running", "paused", "start_pending", "pause_pending", "continue_pending", "stop_pending" or "stopped".

description()

Service long description.

as_dict()

Utility method retrieving all the information above as a dictionary.

4.2.0

Availability: Windows

Example code:

>>> import psutil >>> list(psutil.win_service_iter()) [<WindowsService(name='AeLookupSvc', display_name='Application Experience') at 38850096>, <WindowsService(name='ALG', display_name='Application Layer Gateway Service') at 38850128>, <WindowsService(name='APNMCP', display_name='Ask Update Service') at 38850160>, <WindowsService(name='AppIDSvc', display_name='Application Identity') at 38850192>, ...] >>> s = psutil.win_service_get('alg') >>> s.as_dict() {'binpath': 'C:\Windows\System32\alg.exe', 'description': 'Provides support for 3rd party protocol plug-ins for Internet Connection Sharing', 'display_name': 'Application Layer Gateway Service', 'name': 'alg', 'pid': None, 'start_type': 'manual', 'status': 'stopped', 'username': 'NT AUTHORITY\LocalService'}

Constants

Operating system constants

LINUX

WINDOWS

MACOS

FREEBSD

NETBSD

OPENBSD

BSD

SUNOS

AIX

bool constants which define what platform you're on. E.g. if on Windows, WINDOWS constant will be True, all others will be False.

4.0.0

5.4.0 added AIX

OSX

Alias for MACOS.

Warning

deprecated in version 5.4.7; use MACOS instead.

The path of the /proc filesystem on Linux, Solaris and AIX (defaults to "/proc"). You may want to re-set this constant right after importing psutil in case your /proc filesystem is mounted elsewhere or if you want to retrieve information about Linux containers such as Docker, Heroku or LXC (see here for more info). It must be noted that this trick works only for APIs which rely on /proc filesystem (e.g. memory APIs and most Process class methods).

Availability: Linux, Solaris, AIX

3.2.3

3.4.2 also available on Solaris.

5.4.0 also available on AIX.

Process status constants

STATUS_SLEEPING

STATUS_DISK_SLEEP

STATUS_STOPPED

STATUS_TRACING_STOP

STATUS_ZOMBIE

STATUS_DEAD

STATUS_WAKE_KILL

STATUS_WAKING

STATUS_PARKED (Linux)

STATUS_IDLE (Linux, macOS, FreeBSD)

STATUS_LOCKED (FreeBSD)

STATUS_WAITING (FreeBSD)

STATUS_SUSPENDED (NetBSD)

Represent a process status. Returned by psutil.Process.status().

3.4.1 STATUS_SUSPENDED (NetBSD)

5.4.7 STATUS_PARKED (Linux)

Process priority constants

HIGH_PRIORITY_CLASS

ABOVE_NORMAL_PRIORITY_CLASS

NORMAL_PRIORITY_CLASS

IDLE_PRIORITY_CLASS

BELOW_NORMAL_PRIORITY_CLASS

Represent the priority of a process on Windows (see SetPriorityClass). They can be used in conjunction with psutil.Process.nice() to get or set process priority.

Availability: Windows

IOPRIO_CLASS_RT

IOPRIO_CLASS_BE

IOPRIO_CLASS_IDLE

A set of integers representing the I/O priority of a process on Linux. They can be used in conjunction with psutil.Process.ionice() to get or set process I/O priority. IOPRIO_CLASS_NONE and IOPRIO_CLASS_BE (best effort) is the default for any process that hasn't set a specific I/O priority. IOPRIO_CLASS_RT (real time) means the process is given first access to the disk, regardless of what else is going on in the system. IOPRIO_CLASS_IDLE means the process will get I/O time when no-one else needs the disk. For further information refer to manuals of ionice command line utility or ioprio_get system call.

Availability: Linux

IOPRIO_VERYLOW

IOPRIO_LOW

IOPRIO_NORMAL

IOPRIO_HIGH

A set of integers representing the I/O priority of a process on Windows. They can be used in conjunction with psutil.Process.ionice() to get or set process I/O priority.

Availability: Windows

5.6.2

Process resources constants

Linux / FreeBSD:

RLIM_INFINITY

RLIMIT_AS

RLIMIT_CORE

RLIMIT_CPU

RLIMIT_DATA

RLIMIT_FSIZE

RLIMIT_MEMLOCK

RLIMIT_NOFILE

RLIMIT_NPROC

RLIMIT_RSS

RLIMIT_STACK

Linux specific:

RLIMIT_LOCKS

RLIMIT_MSGQUEUE

RLIMIT_NICE

RLIMIT_RTPRIO

RLIMIT_RTTIME

RLIMIT_SIGPENDING

FreeBSD specific:

RLIMIT_SWAP

RLIMIT_SBSIZE

RLIMIT_NPTS

Constants used for getting and setting process resource limits to be used in conjunction with psutil.Process.rlimit(). See resource.getrlimit for further information.

Availability: Linux, FreeBSD

5.7.3 added FreeBSD support, added RLIMIT_SWAP, RLIMIT_SBSIZE, RLIMIT_NPTS.

Connections constants

CONN_SYN_SENT

CONN_SYN_RECV

CONN_FIN_WAIT1

CONN_FIN_WAIT2

CONN_TIME_WAIT

CONN_CLOSE

CONN_CLOSE_WAIT

CONN_LAST_ACK

CONN_LISTEN

CONN_CLOSING

CONN_NONE

CONN_DELETE_TCB (Windows)

CONN_IDLE (Solaris)

CONN_BOUND (Solaris)

A set of strings representing the status of a TCP connection. Returned by psutil.Process.connections() and psutil.net_connections (status field).

Hardware constants

Constant which identifies a MAC address associated with a network interface. To be used in conjunction with psutil.net_if_addrs().

3.0.0

NIC_DUPLEX_HALF

NIC_DUPLEX_UNKNOWN

Constants which identifies whether a NIC (network interface card) has full or half mode speed. NIC_DUPLEX_FULL means the NIC is able to send and receive data (files) simultaneously, NIC_DUPLEX_FULL means the NIC can either send or receive data at a time. To be used in conjunction with psutil.net_if_stats().

3.0.0

POWER_TIME_UNLIMITED

Whether the remaining time of the battery cannot be determined or is unlimited. May be assigned to psutil.sensors_battery()'s secsleft field.

5.1.0

A tuple to check psutil installed version. Example:

>>> import psutil >>> if psutil.version_info >= (4, 5): ... pass

Recipes

Find process by name

Check string against Process.name():

import psutil

def find_procs_by_name(name):
    "Return a list of processes matching 'name'."
    ls = []
    for p in psutil.process_iter(['name']):
        if p.info['name'] == name:
            ls.append(p)
    return ls

A bit more advanced, check string against Process.name(), Process.exe() and Process.cmdline():

import os
import psutil

def find_procs_by_name(name):
    "Return a list of processes matching 'name'."
    ls = []
    for p in psutil.process_iter(["name", "exe", "cmdline"]):
        if name == p.info['name'] or \
                p.info['exe'] and os.path.basename(p.info['exe']) == name or \
                p.info['cmdline'] and p.info['cmdline'][0] == name:
            ls.append(p)
    return ls

Kill process tree

import os
import signal
import psutil

def kill_proc_tree(pid, sig=signal.SIGTERM, include_parent=True,
                   timeout=None, on_terminate=None):
    """Kill a process tree (including grandchildren) with signal
    "sig" and return a (gone, still_alive) tuple.
    "on_terminate", if specified, is a callabck function which is
    called as soon as a child terminates.
    """
    assert pid != os.getpid(), "won't kill myself"
    parent = psutil.Process(pid)
    children = parent.children(recursive=True)
    if include_parent:
        children.append(parent)
    for p in children:
        try:
            p.send_signal(sig)
        except psutil.NoSuchProcess:
            pass
    gone, alive = psutil.wait_procs(children, timeout=timeout,
                                    callback=on_terminate)
    return (gone, alive)

Filtering and sorting processes

A collection of code samples showing how to use process_iter() to filter processes and sort them. Setup:

>>> import psutil
>>> from pprint import pprint as pp

Processes owned by user:

>>> import getpass
>>> pp([(p.pid, p.info['name']) for p in psutil.process_iter(['name', 'username']) if p.info['username'] == getpass.getuser()])
(16832, 'bash'),
(19772, 'ssh'),
(20492, 'python')]

Processes actively running:

>>> pp([(p.pid, p.info) for p in psutil.process_iter(['name', 'status']) if p.info['status'] == psutil.STATUS_RUNNING])
[(1150, {'name': 'Xorg', 'status': 'running'}),
 (1776, {'name': 'unity-panel-service', 'status': 'running'}),
 (20492, {'name': 'python', 'status': 'running'})]

Processes using log files:

>>> for p in psutil.process_iter(['name', 'open_files']):
...      for file in p.info['open_files'] or []:
...          if file.path.endswith('.log'):
...               print("%-5s %-10s %s" % (p.pid, p.info['name'][:10], file.path))
...
1510  upstart    /home/giampaolo/.cache/upstart/unity-settings-daemon.log
2174  nautilus   /home/giampaolo/.local/share/gvfs-metadata/home-ce08efac.log
2650  chrome     /home/giampaolo/.config/google-chrome/Default/data_reduction_proxy_leveldb/000003.log

Processes consuming more than 500M of memory:

>>> pp([(p.pid, p.info['name'], p.info['memory_info'].rss) for p in psutil.process_iter(['name', 'memory_info']) if p.info['memory_info'].rss > 500 * 1024 * 1024])
[(2650, 'chrome', 532324352),
 (3038, 'chrome', 1120088064),
 (21915, 'sublime_text', 615407616)]

Top 3 processes which consumed the most CPU time:

>>> pp([(p.pid, p.info['name'], sum(p.info['cpu_times'])) for p in sorted(psutil.process_iter(['name', 'cpu_times']), key=lambda p: sum(p.info['cpu_times'][:2]))][-3:])
[(2721, 'chrome', 10219.73),
 (1150, 'Xorg', 11116.989999999998),
 (2650, 'chrome', 18451.97)]

Bytes conversion

import psutil

def bytes2human(n):
    # http://code.activestate.com/recipes/578019
    # >>> bytes2human(10000)
    # '9.8K'
    # >>> bytes2human(100001221)
    # '95.4M'
    symbols = ('K', 'M', 'G', 'T', 'P', 'E', 'Z', 'Y')
    prefix = {}
    for i, s in enumerate(symbols):
        prefix[s] = 1 << (i + 1) * 10
    for s in reversed(symbols):
        if n >= prefix[s]:
            value = float(n) / prefix[s]
            return '%.1f%s' % (value, s)
    return "%sB" % n

total = psutil.disk_usage('/').total
print(total)
print(bytes2human(total))

...prints:

100399730688
93.5G

FAQs

• Q: Why do I get AccessDenied for certain processes?
• A: This may happen when you query processess owned by another user, especially on macOS (see issue #883) and Windows. Unfortunately there's not much you can do about this except running the Python process with higher privileges. On Unix you may run the Python process as root or use the SUID bit (ps and netstat does this). On Windows you may run the Python process as NT AUTHORITY\SYSTEM or install the Python script as a Windows service (ProcessHacker does this).
• Q: is MinGW supported on Windows?
• A: no, you should Visual Studio (see development guide).

Running tests

$ python3 -m psutil.tests

Security

To report a security vulnerability, please use the Tidelift security contact. Tidelift will coordinate the fix and disclosure.

Development guide

If you want to develop psutil take a look at the development guide.

Platforms support history

• psutil 5.7.1 (2020-07): Windows Nano
• psutil 5.7.0 (2020-02): drop Windows XP & Server 2003 support
• psutil 5.7.0 (2020-02): PyPy on Windows
• psutil 5.4.0 (2017-11): AIX
• psutil 3.4.1 (2016-01): NetBSD
• psutil 3.3.0 (2015-11): OpenBSD
• psutil 1.0.0 (2013-07): Solaris
• psutil 0.1.1 (2009-03): FreeBSD
• psutil 0.1.0 (2009-01): Linux, Windows, macOS

Supported Python versions are 2.6, 2.7, 3.4+ and PyPy3.

Timeline

• 2020-12-19: 5.8.0 -what's new -diff
• 2020-10-23: 5.7.3 -what's new -diff
• 2020-07-15: 5.7.2 -what's new -diff
• 2020-07-15: 5.7.1 -what's new -diff
• 2020-02-18: 5.7.0 -what's new -diff
• 2019-11-26: 5.6.7 -what's new -diff
• 2019-11-25: 5.6.6 -what's new -diff
• 2019-11-06: 5.6.5 -what's new -diff
• 2019-11-04: 5.6.4 -what's new -diff
• 2019-06-11: 5.6.3 -what's new -diff
• 2019-04-26: 5.6.2 -what's new -diff
• 2019-03-11: 5.6.1 -what's new -diff
• 2019-03-05: 5.6.0 -what's new -diff
• 2019-02-15: 5.5.1 -what's new -diff
• 2019-01-23: 5.5.0 -what's new -diff
• 2018-10-30: 5.4.8 -what's new -diff
• 2018-08-14: 5.4.7 -what's new -diff
• 2018-06-07: 5.4.6 -what's new -diff
• 2018-04-14: 5.4.5 -what's new -diff
• 2018-04-13: 5.4.4 -what's new -diff
• 2018-01-01: 5.4.3 -what's new -diff
• 2017-12-07: 5.4.2 -what's new -diff
• 2017-11-08: 5.4.1 -what's new -diff
• 2017-10-12: 5.4.0 -what's new -diff
• 2017-09-10: 5.3.1 -what's new -diff
• 2017-09-01: 5.3.0 -what's new -diff
• 2017-04-10: 5.2.2 -what's new -diff
• 2017-03-24: 5.2.1 -what's new -diff
• 2017-03-05: 5.2.0 -what's new -diff
• 2017-02-07: 5.1.3 -what's new -diff
• 2017-02-03: 5.1.2 -what's new -diff
• 2017-02-03: 5.1.1 -what's new -diff
• 2017-02-01: 5.1.0 -what's new -diff
• 2016-12-21: 5.0.1 -what's new -diff
• 2016-11-06: 5.0.0 -what's new -diff
• 2016-10-05: 4.4.2 -what's new -diff
• 2016-10-25: 4.4.1 -what's new -diff
• 2016-10-23: 4.4.0 -what's new -diff
• 2016-09-01: 4.3.1 -what's new -diff
• 2016-06-18: 4.3.0 -what's new -diff
• 2016-05-14: 4.2.0 -what's new -diff
• 2016-03-12: 4.1.0 -what's new -diff
• 2016-02-17: 4.0.0 -what's new -diff
• 2016-01-20: 3.4.2 -what's new -diff
• 2016-01-15: 3.4.1 -what's new -diff
• 2015-11-25: 3.3.0 -what's new -diff
• 2015-10-04: 3.2.2 -what's new -diff
• 2015-09-03: 3.2.1 -what's new -diff
• 2015-09-02: 3.2.0 -what's new -diff
• 2015-07-15: 3.1.1 -what's new -diff
• 2015-07-15: 3.1.0 -what's new -diff
• 2015-06-18: 3.0.1 -what's new -diff
• 2015-06-13: 3.0.0 -what's new -diff
• 2015-02-02: 2.2.1 -what's new -diff
• 2015-01-06: 2.2.0 -what's new -diff
• 2014-09-26: 2.1.3 -what's new -diff
• 2014-09-21: 2.1.2 -what's new -diff
• 2014-04-30: 2.1.1 -what's new -diff
• 2014-04-08: 2.1.0 -what's new -diff
• 2014-03-10: 2.0.0 -what's new -diff
• 2013-11-25: 1.2.1 -what's new -diff
• 2013-11-20: 1.2.0 -what's new -diff
• 2013-10-22: 1.1.2 -what's new -diff
• 2013-10-08: 1.1.1 -what's new -diff
• 2013-09-28: 1.1.0 -what's new -diff
• 2013-07-12: 1.0.1 -what's new -diff
• 2013-07-10: 1.0.0 -what's new -diff
• 2013-05-03: 0.7.1 -what's new -diff
• 2013-04-12: 0.7.0 -what's new -diff
• 2012-08-16: 0.6.1 -what's new -diff
• 2012-08-13: 0.6.0 -what's new -diff
• 2012-06-29: 0.5.1 -what's new -diff
• 2012-06-27: 0.5.0 -what's new -diff
• 2011-12-14: 0.4.1 -what's new -diff
• 2011-10-29: 0.4.0 -what's new -diff
• 2011-07-08: 0.3.0 -what's new -diff
• 2011-03-20: 0.2.1 -what's new -diff
• 2010-11-13: 0.2.0 -what's new -diff
• 2010-03-02: 0.1.3 -what's new -diff
• 2009-05-06: 0.1.2 -what's new -diff
• 2009-03-06: 0.1.1 -what's new -diff
• 2009-01-27: 0.1.0 -what's new -diff