How do I measure separate CPU core usage for a process?

Question

Is there any way to measure a specific process CPU usage by cores?

I know top is good for measuring the whole system\'s CPU usage by cores and taskset can provide inform

Answer 1

You can use:

 mpstat -P ALL 1

It shows how much each core is busy and it updates automatically each second. The output would be something like this (on a quad-core processor):

10:54:41 PM  CPU    %usr   %nice    %sys %iowait    %irq   %soft  %steal  %guest   %idle
10:54:42 PM  all    8.20    0.12    0.75    0.00    0.00    0.00    0.00    0.00   90.93
10:54:42 PM    0   24.00    0.00    2.00    0.00    0.00    0.00    0.00    0.00   74.00
10:54:42 PM    1   22.00    0.00    2.00    0.00    0.00    0.00    0.00    0.00   76.00
10:54:42 PM    2    2.02    1.01    0.00    0.00    0.00    0.00    0.00    0.00   96.97
10:54:42 PM    3    2.00    0.00    0.00    0.00    0.00    0.00    0.00    0.00   98.00
10:54:42 PM    4   14.15    0.00    1.89    0.00    0.00    0.00    0.00    0.00   83.96
10:54:42 PM    5    1.00    0.00    0.00    0.00    0.00    0.00    0.00    0.00   99.00
10:54:42 PM    6    0.00    0.00    0.00    0.00    0.00    0.00    0.00    0.00  100.00
10:54:42 PM    7    0.00    0.00    0.00    0.00    0.00    0.00    0.00    0.00  100.00

This command doesn't answer original question though i.e. it does not show CPU core usage for a specific process.

Answer 2

The ps solution was nearly what I needed and with some bash thrown in does exactly what the original question asked for: to see per-core usage of specific processes

This shows per-core usage of multi-threaded processes too.

Use like: cpustat `pgrep processname` `pgrep otherprocessname` ...

#!/bin/bash

pids=()
while [ $# != 0 ]; do
        pids=("${pids[@]}" "$1")
        shift
done

if [ -z "${pids[0]}" ]; then
        echo "Usage: $0 <pid1> [pid2] ..."
        exit 1
fi

for pid in "${pids[@]}"; do
        if [ ! -e /proc/$pid ]; then
                echo "Error: pid $pid doesn't exist"
                exit 1
        fi
done

while [ true ]; do
        echo -e "\033[H\033[J"
        for pid in "${pids[@]}"; do
                ps -p $pid -L -o pid,tid,psr,pcpu,comm=
        done
        sleep 1
done

Note: These stats are based on process lifetime, not the last X seconds, so you'll need to restart your process to reset the counter.