[Speed] Tracking memory usage

[Victor Stinner]

2016-07-30 19:48 GMT+02:00 Armin Rigo <arigo at tunes.org>:
> Hi Victor,
>
> Fwiw, there is some per-OS (and even apparently
> per-Linux-distribution) solution mentioned here:
> http://stackoverflow.com/questions/774556/peak-memory-usage-of-a-linux-unix-process
>
> For me on Arch Linux, "/usr/bin/time -v CMD" returns a reasonable
> value in "Maximum resident set size (kbytes)".  I guess that on OSes
> where this works, it gives a zero-overhead, exact answer.

Oh, I guess that it uses the ru_maxrss field of
getrsage(RUSAGE_CHILDREN). It's also possible to get the maximum RSS
of the current process in pure Python:

>>> resource.getrusage(resource.RUSAGE_SELF).ru_maxrss
98700

It looks like Linux kernel 2.6.32 or newer is required. Hopefully,
this kernel version is now quite old (December 3rd 2009).

But I guess that RSS is more coarse than getting the sum of the
private memory from /proc/pid/smaps (Linux 2.6.16 or newer). Sadly, it
looks like the kernel only provides the maximum for RSS memory (not
for private memory).

Victor