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I'm using gnu parallel that reads a text file containing curl commands. If I do ps -ef | grep -cw [c]url it shows total number of curl process at a moment.

But I want to know number of gnu parallel jobs running in each CPU core.

How to find that?

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2 Answers 2

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Taking the question literally I do not see a way you can do that: A process may run 1 ms on one core and the next ms it runs on another core.

Your comment is, however, easy to answer:

I wanna ensure all cores are involved. How do I verify that?

htop

This shows all cores are busy:


  1  [|||||93.0%]    17 [|||||97.3%]   33 [|||||87.1%]    49 [|||||91.0%]
  2  [|||||95.3%]    18 [|||||98.5%]   34 [|||||91.4%]    50 [|||||92.5%]
  3  [|||||93.7%]    19 [|||||96.9%]   35 [|||||87.4%]    51 [|||||91.3%]
  4  [|||||90.2%]    20 [|||||96.2%]   36 [|||||92.1%]    52 [|||||94.9%]
  5  [|||||95.3%]    21 [|||||97.3%]   37 [|||||87.6%]    53 [|||||90.7%]
  6  [|||||95.3%]    22 [|||||97.3%]   38 [|||||92.0%]    54 [|||||93.4%]
  7  [|||||91.7%]    23 [|||||97.7%]   39 [|||||86.7%]    55 [|||||94.2%]
  8  [|||||92.5%]    24 [|||||98.4%]   40 [|||||93.3%]    56 [|||||91.8%]
  9  [|||||97.3%]    25 [|||||97.7%]   41 [|||||93.8%]    57 [|||||92.9%]
  10 [|||||97.7%]    26 [|||||96.9%]   42 [|||||94.9%]    58 [|||||93.5%]
  11 [|||||97.7%]    27 [|||||98.4%]   43 [|||||95.3%]    59 [|||||90.8%]
  12 [|||||97.3%]    28 [|||||97.7%]   44 [|||||95.3%]    60 [|||||91.3%]
  13 [|||||96.5%]    29 [|||||97.3%]   45 [|||||95.7%]    61 [|||||93.2%]
  14 [|||||97.7%]    30 [|||||97.7%]   46 [|||||95.3%]    62 [|||||93.3%]
  15 [|||||97.7%]    31 [|||||97.7%]   47 [|||||94.5%]    63 [|||||92.6%]
  16 [|||||96.9%]    32 [|||||95.7%]   48 [|||||94.0%]    64 [|||||94.9%]
  Avg[||||||||||||||||||||||||94.5%]   Tasks: 302, 10084 thr; 39 running
  Mem[|||                10.1G/504G]   Load average: 119.46 47.95 29.59 
  Swp[                        0K/0K]   Uptime: 00:17:23

    PID USER      PRI  NI  VIRT   RES   SHR S CPU% MEM%   TIME+  Command
   2457 vcache     20   0 4985M 1284M 86536 S 440.  0.2 10:54.69 /usr/sbin/varn
 351883 www-data   20   0 1954M 11736  3748 S 142.  0.0  1:20.80 /usr/sbin/apac
 433876 www-data   20   0 1953M 11392  3748 S 132.  0.0  0:29.07 /usr/sbin/apac
 411605 www-data   20   0 1889M 11424  3748 S 99.0  0.0  0:40.96 /usr/sbin/apac
   2466 varnishlo  20   0 87080 84156 83468 S 42.6  0.0  1:07.94 /usr/bin/varni
 371877 tange      20   0 15916 11136  3500 R 40.3  0.0  0:24.92 htop
 372227 tange      20   0 25960 19820  5688 D 33.2  0.0  0:15.86 perl /usr/loca
 372060 tange      20   0 25912 19816  5692 D 32.5  0.0  0:15.21 perl /usr/loca
F1Help  F2Setup F3SearchF4FilterF5Tree  F6SortByF7Nice -F8Nice +F9Kill  F10Quit

This shows an idle machine:


  1  [|     0.5%]    17 [      0.0%]   33 [      0.0%]    49 [      0.0%]
  2  [      0.0%]    18 [      0.0%]   34 [      0.0%]    50 [      0.0%]
  3  [      0.0%]    19 [      0.0%]   35 [      0.0%]    51 [      0.0%]
  4  [      0.0%]    20 [      0.0%]   36 [      0.0%]    52 [      0.0%]
  5  [      0.0%]    21 [|     0.5%]   37 [      0.0%]    53 [      0.0%]
  6  [      0.0%]    22 [      0.0%]   38 [      0.0%]    54 [      0.0%]
  7  [      0.0%]    23 [      0.0%]   39 [      0.0%]    55 [      0.0%]
  8  [|||| 29.6%]    24 [      0.0%]   40 [      0.0%]    56 [      0.0%]
  9  [|     0.5%]    25 [|     0.5%]   41 [|     0.5%]    57 [|     0.9%]
  10 [      0.0%]    26 [|     0.5%]   42 [      0.0%]    58 [|     0.5%]
  11 [      0.0%]    27 [||    0.9%]   43 [      0.0%]    59 [|     0.9%]
  12 [      0.0%]    28 [|     0.5%]   44 [      0.0%]    60 [|     0.5%]
  13 [      0.0%]    29 [|     0.5%]   45 [|     0.5%]    61 [|     0.9%]
  14 [      0.0%]    30 [|     0.5%]   46 [|     0.5%]    62 [|     0.9%]
  15 [      0.0%]    31 [|     0.5%]   47 [|     0.5%]    63 [||    1.4%]
  16 [      0.0%]    32 [|     0.5%]   48 [      0.0%]    64 [|     0.9%]
  Avg[||                       0.7%]   Tasks: 132, 10350 thr; 1 running
  Mem[|||                7.15G/504G]   Load average: 1.02 21.86 20.72 
  Swp[                        0K/0K]   Uptime: 00:15:10 

    PID USER      PRI  NI  VIRT   RES   SHR S CPU% MEM%   TIME+  Command
   2457 vcache     20   0 4913M 1191M 86520 S  0.5  0.2  7:02.69 /usr/sbin/varn
   3023 mysql      20   0 2092M  377M 35696 S  0.5  0.1  0:00.50 /usr/sbin/mysq
   4217 root       20   0 2366M 44548 19464 S  0.5  0.0  0:00.12 /usr/lib/snapd
 371811 root       20   0 23436  5048  1892 S  0.0  0.0  0:00.03 /lib/systemd/s
 371814 root       20   0 23436  5048  1892 S  0.0  0.0  0:00.03 /lib/systemd/s
 371816 root       20   0 23436  5048  1892 S  0.0  0.0  0:00.03 /lib/systemd/s
 371817 root       20   0 23436  5048  1892 S  0.0  0.0  0:00.03 /lib/systemd/s
 371818 root       20   0 23436  5048  1892 S  0.0  0.0  0:00.03 /lib/systemd/s
F1Help  F2Setup F3SearchF4FilterF5Tree  F6SortByF7Nice -F8Nice +F9Kill  F10Quit
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0

That number is 0 or 1. A CPU core can only execute one program at a time.

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5
  • BUt aren't there more cores in recent machines? especially Macbooks.
    – sofs1
    Jan 7 at 22:33
  • yes, but you ask "how many processes per core at any given instant" and the answer is "at most 1". A core executes one process at a time. You can start more processes than you have cores. But then they wait to take turns on the cores.
    – Marcus Müller
    Jan 7 at 22:34
  • Got it. I wanna ensure all cores are involved. How do I verify that?
    – sofs1
    Jan 7 at 22:35
  • Unless you explicitly told your operating system that should not happen, it will happen. There's really nothing much to verify.
    – Marcus Müller
    Jan 7 at 22:36
  • ah you're the person with the 10000 requests per second via xargs :) honestly, will still not happen, but if you could go to my answer there and comment on it, what you took from it (and what not), it would certainly make my day.
    – Marcus Müller
    Jan 7 at 22:40

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