This is a simple utility for estimating idle memory size. A memory page is considered idle if it has not been accessed for more than the given amount of time. Knowing a workload's idle memory size can be used for estimating its working set size (wss).
idlememstat will scan memory periodically, count pages that has not
been touched since the previous scan, and print this information to
stdout. To ease estimating the idle memory size of a particular
workload, this information is gathered and reported per memory cgroup so
that one can put the workload of interest to a memory cgroup and filter
the output of idlememstat accordingly. To avoid CPU bursts, each scan
performed by idlememstat is evenly distributed in time.
Note, idlememstat does not consider unused mlocked pages as idle.
- Linux kernel with
CONFIG_IDLE_PAGE_TRACKINGset (4.3+ required) g++with c++11 supportpython-2.7+ devel package- memory cgroup controller must be mounted under
/sys/fs/cgroup/memory(this is what systemd normally does)
python setup.py install
idlememstat [delay]
delay (equals 300 if omitted) is time, in seconds after which a page
will be considered idle if not accessed by a userspace process.
Example:
cgroup total idle anon anon_idle file file_idle
/ 166436 117720 78772 51728 87664 65992
/test 114072 85084 5152 0 108920 85084
/ 166488 158916 78824 63596 87664 95320
/test 114072 114072 5152 5152 108920 108920
cgroup- relative path to memory cgrouptotal- user memory size, in kBidle- idle user memory size, in kBanon- anonymous memory size, in kBanon_idle- idle anonymous memory size, in kBfile- file memory size (both mapped and unmapped), in kBfile_idle- idle file memory size (both mapped and unmapped), in kB