Date: Mon, 30 Aug 2010 11:09:32 +0200 From: Gary Jennejohn <gljennjohn@googlemail.com> To: Alexander Motin <mav@FreeBSD.org> Cc: freebsd-hackers@freebsd.org, FreeBSD-Current <freebsd-current@freebsd.org> Subject: Re: One-shot-oriented event timers management Message-ID: <20100830110932.23425932@ernst.jennejohn.org> In-Reply-To: <4C7A5C28.1090904@FreeBSD.org> References: <4C7A5C28.1090904@FreeBSD.org>
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On Sun, 29 Aug 2010 16:10:00 +0300 Alexander Motin <mav@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: 1122 hpet0:t0 1124 hpet0:t1 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 :( -- Gary Jennejohn
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