Messages in this thread | | | Date | Mon, 9 Nov 2009 14:29:17 +0100 | Subject | Re: [PATCH v2] cpuidle: Fix the menu governor to boost IO performance | From | Corrado Zoccolo <> |
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On Sun, Nov 8, 2009 at 11:30 PM, Arjan van de Ven <arjan@infradead.org> wrote: > On Sun, 8 Nov 2009 22:59:43 +0100 > I think we all agree that long term polling is bad ;-) > (even though we use rep nop in the polling loop which is also a HT > yield). > > There's just the very short sleeps (where short is "single digit usecs") > where the rules are slightly different. > >> > this check is supposed to catch the known timer cases; those >> > are rather accurate in prediction >> >> Unfortunately, I have seen polling residency times > 1ms, so it must >> not be so accurate. > > well the question is... is this a measurement error or an error in > when polling is chosen. > We obviously need to fix it whatever it is, but... first need to chase > down really which it is.
Any suggestion on how to check? Clocksource is hpet, and I have CONFIG_SCHED_HRTICK=y, so the granularity should not be a problem.
Corrado
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