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pistacchio
Asked: 2010-01-04 10:10:43 +0800 CST

*nix measure memory usage

  • 772

i'd like to measure the total memory (like RAM) used by a program during its execution. Ideally, something like time that runs the program and print stats when it exits.

Is there such a standard tool in the unix / linux / bsd world? Thanks.

EDIT:

the program i'm trying to profile takes fractions of a second to execute, so anything that implies "while running check this" won't work. that's why i'm asking for a "time" like tool.

unix

7 Answers

  1. The strace command might be of some use. It will show you in what system calls the time is being taken up:

    $ strace -cTv zip /tmp/test.zip /usr/share/dict/words
  adding: usr/share/dict/words (deflated 73%)
% time     seconds  usecs/call     calls    errors syscall
------ ----------- ----------- --------- --------- ----------------
100.00    0.000055           2        34           read
  0.00    0.000000           0        21           write
  0.00    0.000000           0        12         3 open
  0.00    0.000000           0         9           close
  0.00    0.000000           0         3         3 access
  0.00    0.000000           0         1           rename
  0.00    0.000000           0         3           brk
  0.00    0.000000           0         1           gettimeofday
  0.00    0.000000           0         4           munmap
  0.00    0.000000           0         3           mprotect
  0.00    0.000000           0         6           _llseek
  0.00    0.000000           0         6           rt_sigaction
  0.00    0.000000           0        12           mmap2
  0.00    0.000000           0         8         1 stat64
  0.00    0.000000           0         1         1 lstat64
  0.00    0.000000           0         9           fstat64
  0.00    0.000000           0         1           fcntl64
  0.00    0.000000           0         1           set_thread_area
------ ----------- ----------- --------- --------- ----------------
100.00    0.000055                   141         8 total
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  2. On Linux you can read /proc/[pid]/status; the VmPeak field is the maximum virtual memory size, VmHWM is the maximum resident set size.

    The getrusage() syscall might, or might not, help. The struct rusage contains e.g. a maxrss field, but at least on Linux this is never filled in.

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  3. If you don't mind repeating the execution a few times you can use ulimit -Hv to set the memory limit for the shell (in Bash) and then binary search the minimum when the application successfully exits.

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  4. I'd suggest valgrind. The massif app will report heap usage stats, at least.

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  5. No standard tool except ps (which is not so standard in regards to options/output too). This will not give you time-like usability.

    You can use nmon to gather system-wide statistics, it captures memory usage of processes (it will be probably useless for short-lived processes). It supports many platforms.

    • 0

  6. You could try writing your own script that could do this. It could get the PID of the launched program and use ps or /proc/[pid]/status to get memory information about it. Of course this wouldn't totally characterize the memory usage but it should give you a good idea.

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  7. Just use process accounting (acct or psacct depending on your distribution). The process accounting log includes "memory used" statistics.

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