Peak memory usage of a linux/unix process [closed]

[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 

(This is an already answered, old question.. but just for the record :)

I was inspired by Yang's script, and came up with this small tool, named memusg. I simply increased the sampling rate to 0.1 to handle much short living processes. Instead of monitoring a single process, I made it measure rss sum of the process group. (Yeah, I write lots of separate programs that work together) It currently works on Mac OS X and Linux. The usage had to be similar to that of time:

 memusg ls -alR / >/dev/null 

It only shows the peak for the moment, but I'm interested in slight extensions for recording other (rough) statistics.

It's good to have such simple tool for just taking a look before we start any serious profiling.

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 . . . 

Valgrind one-liner:

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

Note use of --pages-as-heap to measure all memory in a process. More info here: http://valgrind.org/docs/manual/ms-manual.html

This will slow down your command significantly.

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.

On MacOS Sierra use:

/usr/bin/time -l commandToMeasure 

You can use grep to take what you want maybe.

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

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

See time(1) for details...

time -f '%M' <run_program> 

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 

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 

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.

You can use a tool like Valgrind to do this.

Here is (based on the other answers) a very simple script that watches an already running process. You just run it with the pid of the process you want to watch as the argument:

#!/usr/bin/env bash pid=$1 while ps $pid >/dev/null do ps -o vsz= ${pid} sleep 1 done | sort -n | tail -n1 

Example usage:

max_mem_usage.sh 23423 

Heaptrack is KDE tool that has a GUI and text interface. I find it more suitable than valgrind to understand the memory usage of a process because it provides more details and flamegraphs. It's also faster because it does less checking that valgrind. And it gives you the peak memory usage.

Anyway, tracking rss and vss is misleading because pages could be shared, that's why that memusg. What you should really do is track the sum of Pss in /proc/[pid]/smaps or use pmap. GNOME system-monitor used to do so but it was too expensive.

Use Massif: http://valgrind.org/docs/manual/ms-manual.html

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

On macOS, you can use DTrace instead. The "Instruments" app is a nice GUI for that, it comes with XCode afaik.

'htop' is best command for see which process is using how much RAM.....

for more detail http://manpages.ubuntu.com/manpages/precise/man1/htop.1.html