smem memory reporting tool

smem is a tool that can give numerous reports on memory usage on Linux systems. Unlike existing tools, smem can report proportional set size (PSS), which is a more meaningful representation of the amount of memory used by libraries and applications in a virtual memory system.

Because large portions of physical memory are typically shared among multiple applications, the standard measure of memory usage known as resident set size (RSS) will significantly overestimate memory usage. PSS instead measures each application's "fair share" of each shared area to give a realistic measure.

smem has many features:

system overview listing
listings by process, mapping, user
filtering by process, mapping, or user
configurable columns from multiple data sources
configurable output units and percentages
configurable headers and totals
reading live data from /proc
reading data snapshots from directory mirrors or compressed tarballs
lightweight capture tool for embedded systems
built-in chart generation

smem has a few requirements:

a reasonably modern kernel (> 2.6.27 or so)
a reasonably recent version of Python (2.4 or so)
the matplotlib library for chart generation (optional, auto-detected)

Sample output

Here are some smem graphs showing how RSS exaggerates memory usage. Note how apps that share libraries are over-reported on the RSS side and nearly vanish on the PSS side. The X server is also shares memory heavily, it's real memory usage is about 5 times smaller.

Using smem

Show basic process information smem

Show library-oriented view smem -m

Show user-oriented view smem -u

Show system view smem -R 4G -K /path/to/vmlinux -w

Show totals and percentages smem -t -p

Show different columns smem -c "name user pss"

Sort by reverse RSS smem -s rss -r

Show processes filtered by mapping smem -M libxml

Show mappings filtered by process smem -m -P [e]volution

Read data from capture tarball smem --source capture.tar.gz

Show a bar chart labeled by pid smem --bar pid -c "pss uss"

Show a pie chart of RSS labeled by name smem --pie name -s rss

Getting smem

To get the latest release version, click here.

The latest source code can be grabbed from smem's Mercurial repository here with the command:

hg clone http://selenic.com/repo/smem

Feedback

Write to the smem list at smem@selenic.com.