Monitor average CPU usage and RAM usage on one process linux

Question

Is there any way to monitor one process' CPU usage and RAM usage over time on linux? I am trying to change to a cheaper VPS and need to work out what level of CPU and RAM I need!

Solution 1

read man 5 proc, especially the /proc/[pid]/stat entry and the utime, stime fields. /proc/[pid]/status or /proc/[pid]/statm might be of interest for you as well.

then use cron or whatever means needed to collect 'snapshots' of /proc/[pid]/stat for your process over a period of time. then visualize what you have grabbed.

a simple 'collector' works like this (for a process with the pid '29777'):

% while true; do cat /proc/29777/stat; sleep 1; done

to make life easier, you could also use the systat package which includes several means to collect data over time:

http://sebastien.godard.pagesperso-orange.fr/documentation.html

Solution 2

pidstat is a very good tool for the cpu part of your question.

http://xmodulo.com/2012/08/how-to-measure-average-cpu-utilization.html

Comments

[Ryan C. Thompson]

Shouldn't you be more interested in maximum memory usage?

[Ryan C. Thompson]

Top only provides instantaneous snapshots of CPU and memory usage. The OP asks how to collect aggregate statistics over time.

[Pez Cuckow]

Sounds an interesting idea, i'll give it a go and update you with the result.