Peak memory usage of a linux/unix process

[Edit: Works on Ubuntu 14.04: /usr/bin/time -v command Make sure to use the full path.]

Looks like /usr/bin/time does give you that info, if you pass -v (this is on Ubuntu 8.10). See, e.g., Maximum resident set size below:

$ /usr/bin/time -v ls /
....
        Command being timed: "ls /"
        User time (seconds): 0.00
        System time (seconds): 0.01
        Percent of CPU this job got: 250%
        Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.00
        Average shared text size (kbytes): 0
        Average unshared data size (kbytes): 0
        Average stack size (kbytes): 0
        Average total size (kbytes): 0
        Maximum resident set size (kbytes): 0
        Average resident set size (kbytes): 0
        Major (requiring I/O) page faults: 0
        Minor (reclaiming a frame) page faults: 315
        Voluntary context switches: 2
        Involuntary context switches: 0
        Swaps: 0
        File system inputs: 0
        File system outputs: 0
        Socket messages sent: 0
        Socket messages received: 0
        Signals delivered: 0
        Page size (bytes): 4096
        Exit status: 0

On Linux:

Use /usr/bin/time -v <program> <args> and look for "Maximum resident set size".

(Not to be confused with the Bash time built-in command! So use the full path, /usr/bin/time)

For example:

> /usr/bin/time -v ./myapp
        User time (seconds): 0.00
        . . .
        Maximum resident set size (kbytes): 2792
        . . .

On BSD, MacOS:

Use /usr/bin/time -l <program> <args>, looking for "maximum resident set size":

>/usr/bin/time -l ./myapp
        0.01 real         0.00 user         0.00 sys
      1440  maximum resident set size
      . . .

Here's a one-liner that doesn't require any external scripts or utilities and doesn't require you to start the process via another program like Valgrind or time, so you can use it for any process that's already running:

grep ^VmPeak /proc/$PID/status

(replace $PID with the PID of the process you're interested in)

Perhaps (gnu) time(1) already does what you want. For instance:

$ /usr/bin/time -f "%P %M" command
43% 821248

But other profiling tools may give more accurate results depending on what you are looking for.

/usr/bin/time maybe does what you want, actually. Something like.

 /usr/bin/time --format='(%Xtext+%Ddata %Mmax)'

See time(1) for details...

If the process runs for at least a couple seconds, then you can use the following bash script, which will run the given command line then print to stderr the peak RSS (substitute for rss any other attribute you're interested in). It's somewhat lightweight, and it works for me with the ps included in Ubuntu 9.04 (which I can't say for time).

#!/usr/bin/env bash
"$@" & # Run the given command line in the background.
pid=$! peak=0
while true; do
  sleep 1
  sample="$(ps -o rss= $pid 2> /dev/null)" || break
  let peak='sample > peak ? sample : peak'
done
echo "Peak: $peak" 1>&2

time -f '%M' <run_program>

Well, if you really want to show the memory peak and some more in-depth statistics i recommend using a profiler such as valgrind. A nice valgrind front-end is alleyoop.

Because /usr/bin/time is not present in many modern distributions (Bash built-in time instead), you can use Busybox time implementation with -v argument:

busybox time -v uname -r

It's output is similar to GNU time output. Busybox is pre-installed in most Linux distros (Debian, Ubuntu, etc.). If you using Arch Linux, you can install it with:

sudo pacman -S busybox

You can use a tool like Valgrind to do this.

Re-inventing the wheel, with hand made bash script. Quick and clean.

My use case: I wanted to monitor a linux machine which has less RAM and wanted to take a snapshot of per container usage when it runs under heavy usage.

#!/usr/bin/env bash

threshold=$1

echo "$(date '+%Y-%m-%d %H:%M:%S'): Running free memory monitor with threshold $threshold%.."

while(true)
    freePercent=`free -m | grep Mem: | awk '{print ($7/$2)*100}'`    
  do

  if (( $(awk 'BEGIN {print ("'$freePercent'" < "'$threshold'")}') ))
  then
       echo "$(date '+%Y-%m-%d %H:%M:%S'): Free memory $freePercent% is less than $threshold%"
       free -m
       docker stats --no-stream
       sleep 60  
       echo ""  
  else
       echo "$(date '+%Y-%m-%d %H:%M:%S'): Sufficient free memory available: $freePercent%"
  fi
  sleep 30

done

Sample output:

2017-10-12 13:29:33: Running free memory monitor with threshold 30%..

2017-10-12 13:29:33: Sufficient free memory available: 69.4567%

2017-10-12 13:30:03: Sufficient free memory available: 69.4567%

2017-10-12 16:47:02: Free memory 18.9387% is less than 30%

your custom command output

Please be sure to answer the question. Provide details and share your research!

Sorry, I am first time here and can only ask questions…

Used suggested:

valgrind --tool=massif --pages-as-heap=yes --massif-out-file=massif.out ./test.sh; grep mem_heap_B massif.out | sed -e 's/mem_heap_B=\(.*\)/\1/' | sort -g | tail -n 1

then:

grep mem_heap_B massif.out
...
mem_heap_B=1150976
mem_heap_B=1150976
...

this is very different from what top command shows at similar moment:

14673 gu27mox   20   0 3280404 468380  19176 R 100.0  2.9   6:08.84 pwanew_3pic_com

what are measured units from Valgrind??

The /usr/bin/time -v ./test.sh never answered — you must directly feed executable to /usr/bin/time like:

/usr/bin/time -v  pwanew_3pic_compass_2008florian3_dfunc.static  card_0.100-0.141_31212_resubmit1.dat_1.140_1.180   1.140 1.180 31212


    Command being timed: "pwanew_3pic_compass_2008florian3_dfunc.static card_0.100-0.141_31212_resubmit1.dat_1.140_1.180 1.140 1.180 31212"

    User time (seconds): 1468.44
    System time (seconds): 7.37
    Percent of CPU this job got: 99%
    Elapsed (wall clock) time (h:mm:ss or m:ss): 24:37.14
    Average shared text size (kbytes): 0
    Average unshared data size (kbytes): 0
    Average stack size (kbytes): 0
    Average total size (kbytes): 0
    Maximum resident set size (kbytes): 574844
    Average resident set size (kbytes): 0
    Major (requiring I/O) page faults: 74
    Minor (reclaiming a frame) page faults: 468880
    Voluntary context switches: 1190
    Involuntary context switches: 20534
    Swaps: 0
    File system inputs: 81128
    File system outputs: 1264
    Socket messages sent: 0
    Socket messages received: 0
    Signals delivered: 0
    Page size (bytes): 4096
    Exit status: 0