From: Corrado Zoccolo <czoccolo@gmail.com>
To: Arjan van de Ven <arjan@infradead.org>
Cc: linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
lenb@kernel.org, mingo@elte.hu, yanmin_zhang@linux.intel.com,
jens.axboe@oracle.com, Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Subject: Re: [PATCH v2] cpuidle: Fix the menu governor to boost IO performance
Date: Mon, 9 Nov 2009 14:29:17 +0100 [thread overview]
Message-ID: <4e5e476b0911090529g6ba93a9o91cfc1b15d7497d1@mail.gmail.com> (raw)
In-Reply-To: <20091108143059.029abf8b@infradead.org>
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
next prev parent reply other threads:[~2009-11-09 13:29 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-15 3:42 Arjan van de Ven
2009-09-15 3:54 ` Andrew Morton
2009-09-15 4:15 ` Arjan van de Ven
2009-09-15 4:18 ` Arjan van de Ven
2009-09-15 5:03 ` Rik van Riel
2009-09-15 23:23 ` Andrew Morton
2009-09-16 4:35 ` Arjan van de Ven
2009-09-17 13:39 ` Arjan van de Ven
2009-11-04 9:39 ` Corrado Zoccolo
2009-11-08 20:40 ` Arjan van de Ven
2009-11-08 21:59 ` Corrado Zoccolo
2009-11-08 22:30 ` Arjan van de Ven
2009-11-09 13:29 ` Corrado Zoccolo [this message]
2009-11-08 22:39 ` Arjan van de Ven
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