QMemstat is a tool to inspect the address space of a process.
The Linux kernel exposes quite detailed information about the memory pages that processes use, and information about the pages themselves, which can be put together to get detailed information about a given process. qmemstat uses this information from the kernel and shows it in a more convenient format. Since the kernel interfaces used are root-only for security reasons, qmemstat needs to run as root, or at least a "server" needs to run as root for qmemstat.
QMemstat contains two related tools:
Command-line tool. It must be run as root.
memstat has two modes:
- display memory use information:
memstat <pid>|<process-name>outputs the following three numbers:- VSZ (virtual set size): the size of the address space of the process
- RSS (resident set size): the size of physical memory in the address space of the process
- PSS (proportional set size): like RSS, but for shared memory pages the size is divided by the number of users. This is the most accurate "actual memory used" value.
- server mode:
memstat <pid>|<process> --server <port-number>continuously grabs address space information and provides it to qmemstat (see below).
GUI tool which shows information about a process's address space, and which updates the information continuously.
It has two modes:
- standalone:
qmemstat <pid>|<process-name>(must be run as root) shows a graphical view of the address space of the process.- Hold down the left mouse button to see the flags of the page under the cursor in the panel on the left.
- as a client to memstat running in server mode (does not need root):
qmemstat --client <server-address> <port-number>Otherwise it works like standalone mode.