ps utility in linux (procps), how to check which CPU is used

Question

It is about procps package, utility ps for linux.

Can it print the number of last used CPU for each process (thread)?

Update: Not a CPU Time (10 seconds), but a CPU NUMBER (CPU0,CPU5,CPU123)

Mikel · Answer 1 · 2011-04-21T00:59:03.673

The ps(1) man page says you can use the psr field:

   psr        PSR     processor that process is currently assigned to.

$ ps -o pid,psr,comm
  PID PSR COMMAND
 7871   1 bash
 9953   3 ps

Or you can use the cpuid field, which does the same thing.

$ ps -o pid,cpuid,comm
  PID CPUID COMMAND
 7871     1 bash
10746     3 ps

The reason for two names is for compatibility with Solaris (psr) and NetBSD/OpenBSD (cpuid).

To get threads too, add the -L option (and the lwp field if you are using -o).

Without threads:

$ ps -U $USER -o pid,psr,comm | egrep 'chromi|PID' | head -4
  PID PSR COMMAND
 6457   3 chromium-browse
 6459   0 chromium-browse
 6461   2 chromium-browse

With threads:

$ ps -U $USER -L -o pid,lwp,psr,comm | egrep 'chromi|PID' | head -4
  PID   LWP PSR COMMAND
 6457  6457   3 chromium-browse
 6457  6464   1 chromium-browse
 6457  6465   2 chromium-browse

There's also an undocumented -P option, which adds psr to the normal fields:

$ ps -U $USER -LP | egrep 'chromi|PID' | head -4
  PID   LWP PSR TTY          TIME CMD
 6457  6457   3 ?        00:01:19 chromium-browse
 6457  6464   1 ?        00:00:00 chromium-browse
 6457  6465   2 ?        00:00:00 chromium-browse

There's also a `-P` option, which isn't documented, but saves some typing. — Mikel, Apr 21 '11 at 00:11

jcomeau_ictx · Accepted Answer · 2011-04-20T21:26:57.823

4

which of multiple processors? it does not offer an option for that according to the manpage. but on my Debian stable system it accepts the undocumented -o cpu

after looking at the source, and the output of ps L, I believe your answer is either the cpuid or sgi_p output options, column IDs CPUID and P, respectively.

And 'cpu' should work according to this note in output.c, but it's currently tied to the 'nop' output pr_nop():

{"cpu", "CPU", pr_nop, sr_nop, 3, 0, BSD, AN|RIGHT}, /* FIXME ... HP-UX wants this as the CPU number for SMP? */

edited Apr 20 '11 at 21:26

answered Apr 20 '11 at 14:49

jcomeau_ictx

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no, it doesn't. Not a CPU time, but `Number of last used CPU` (CPU0,CPU1,CPU2) as it is in `top` "f" "j" `J: P = Last used cpu (SMP)` – osgx Apr 20 '11 at 14:55
But `top` from same `procps` can. – osgx Apr 20 '11 at 14:56
I see that and agree. But there is no such option in ps as documented by the manpage. – jcomeau_ictx Apr 20 '11 at 14:58
aha! try -o cpu; it accepts it, but on my single-processor system only shows "-" – jcomeau_ictx Apr 20 '11 at 14:59
on my 4cpu system it is also `-` for all processes ( – osgx Apr 20 '11 at 15:03
please see my latest edit, hopefully one of those options will serve your needs. – jcomeau_ictx Apr 20 '11 at 20:33

score 3 · Answer 3 · answered Sep 05 '18 at 20:15

I did it this way on Arch, it might help someone out there:

ps -C "process" -L -o pid,lwp,pcpu,cpuid,time

-C: select the process named "process"
-L: list the process threads
-o: specify output info
- pid: process id
- lwp: light weight process (thread)
- pcpu: CPU usage (percent)
- cpuid: CPU id
- time: thread time (from start)

score 3 · Answer 4 · answered Apr 20 '11 at 21:40

3

Also much underrated:

mpstat -I ALL 1 | less -SR

answered Apr 20 '11 at 21:40

sehe

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Is it available in old ubuntu? – osgx Apr 20 '11 at 21:41
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It was already available in [Dapper (2006)](http://packages.ubuntu.com/dapper/sysstat) and lives in package `sysstat`. Haven't looked farther back though – sehe Apr 20 '11 at 21:47
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For that matter, you can run `top` and press `1` (number 1) to see workload per CPU. – Mikel Apr 21 '11 at 00:31

ps utility in linux (procps), how to check which CPU is used

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