Date: Mon, 30 Aug 2010 13:07:38 +0300 From: Alexander Motin <mav@FreeBSD.org> To: gljennjohn@googlemail.com Cc: freebsd-hackers@freebsd.org, FreeBSD-Current <freebsd-current@freebsd.org> Subject: Re: One-shot-oriented event timers management Message-ID: <4C7B82EA.2040104@FreeBSD.org> In-Reply-To: <20100830110932.23425932@ernst.jennejohn.org> References: <4C7A5C28.1090904@FreeBSD.org> <20100830110932.23425932@ernst.jennejohn.org>
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Gary Jennejohn wrote: > 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 It means 1000Hz of hardclock (hz) events mixed with 127Hz of statclock (stathz) events. HPET timer here works in one-shot mode handling it. > 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 :( Yes, as I have said, at this moment empty ticks skipped only while CPU is in C2/C3 states. In C1 state there is no way to handle lost events on wake up. While it may be not very dangerous, it is not very good. -- Alexander Motin
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