Re: [Xenomai-help] x86_64 user/system process accounting

[Jan Kiszka <jan.kiszka@domain.hid>]

Kyle Howell wrote:
>> Jan Kiszka wrote:
>>>>>>>> Kyle Howell wrote:
>>>>>>>> I'm running Xenomai 2.4.1 against Linux 2.6.23.12 on an
>>>>>>>> x86_64 (Core2)
>>>>>>>> system. I'm finding that all of my CPU cycles are being 
>>>>>>>> accounted as kernel time rather than user time. The correct 
>>>>>>>> processes are still billed, but the system is always 0% user. 
>> And here comes a fix:
>>
>> In rthal_timer_set_oneshot() we assume that the hijacked APIC 
>> timer will also be used to for emulating host ticks, thus 
>> __ipipe_tick_irq is set accordingly. But this is not true for 
>> x86-64 over non-clockevent kernels (2.6.23...), so we have to 
>> fixup __ipipe_tick_irq with the correct number (first patch).
> 
> cat /proc/stat
> cpu  9562 0 418 166028 12 0 2 0
> cpu0 1208 0 118 20706 0 0 0 0 
> 
> Ahh... That feels much better. Thanks a lot, Jan. I think that would
> have taken me a long, long time to find on my own. BTW, I hope that you
> didn't stay up until 5 in the morning on my account.

Not till 5... :->

Unfortunately I just had to learn from my colleague that the problem is
not fully solved (for good-old 2.6.23).

So I'm banging my head against it again, and I think I understood that
SMP can still account the load to the wrong context any CPU except the
one that receives its ticks via RTHAL_BCAST_TICK_IRQ. Back to the
drawing board to design a better workaround...

Jan - who's happy that 2.6.24 cleans up with the timer mess

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