One-shot-oriented event timers management
gljennjohn at googlemail.com
Mon Aug 30 09:09:37 UTC 2010
On Sun, 29 Aug 2010 16:10:00 +0300
Alexander Motin <mav at FreeBSD.org> wrote:
> I have actively tested this code for a few days on my amd64 Core2Duo
> laptop and i386 Core-i5 desktop system. With C2/C3 states enabled
> systems experience only about 100-150 interrupts per second, having HZ
> set to 1000. These events mostly caused by several event-greedy
> processes in our tree. I have traced and hacked several most aggressive
> ones in this patch: http://people.freebsd.org/~mav/tm6292_idle.patch .
> It allowed me to reduce down to as low as 50 interrupts per system,
> including IPIs! Here is the output of `systat -vm 1` from my test
> system: http://people.freebsd.org/~mav/systat_w_oneshot.txt . Obviously
> that with additional tuning the results can be improved even more.
Hmm. I applied your patches and am now running the new kernel. But I
only installed the new kernel and didn't do make buildworld installworld.
Mu systat -vm 1 doesn't look anything like yours. I'm seeing about 2300
interrupts per second and most of those are coming from the hpet timers:
So, what else did you do to reduce interrupts so much?
Ah, I think I see it now. My desktop has only C1 enabled. Is that it?
Unfortunately, it appears that only C1 is supported :(
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