Messages in this thread | | | Date | Mon, 16 Apr 2012 14:36:06 +0200 | From | Martin Schwidefsky <> | Subject | Re: /proc/stat information incorrect |
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On Mon, 16 Apr 2012 10:04:48 +0200 Bas van der Oest <bassvdo@gmail.com> wrote:
> After dropping some zero columns and taking the difference between the > statistics the reformatted result is: > user nice system idle iowait irq softirq sum > cpu 5 0 434 7676 0 0 53 8168 > cpu0 0 0 0 1067 0 0 0 1067 > cpu1 0 0 1 1070 0 0 0 1071 > cpu2 0 0 0 1071 0 0 0 1071 > cpu3 1 0 0 1070 0 0 0 1071 > cpu4 1 0 94 974 0 0 0 1069 > cpu5 2 0 92 535 0 0 52 681 > cpu6 0 0 82 987 0 0 0 1069 > cpu7 1 0 165 905 0 0 0 1071 > > I added a sum column which totals the time spent in the different > modes. The above table now shows how long each CPU was in what mode > for how long. > Now I am wondering how it is possible that CPU5 has spent much less > time than all the other CPUs. I expected that all CPUs spent around > the same time (10s). This time includes idle time so this is not > related to the difference in active/idle CPUs. > > I know for a fact that this effect is related to which CPU is handling > my IRQs; this effect happens to all CPUs if I map the interrupts to > that particular CPU. > I looked up the scheduler's statistics handling in the kernel source > but was not able to find any cause for the above mentioned effect. > > Can anyone reproduce this behaviour? > Does anyone know where/what might be the cause of this?
Assuming that you are on a recent kernel (>= 3.2), could you please try to revoke git commit a25cac5198d4ff28 "proc: Consider NO_HZ when printing idle and iowait times" and try again ?
-- blue skies, Martin.
"Reality continues to ruin my life." - Calvin.
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