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From: Ingo Molnar <mingo@elte.hu>
To: Guillaume Chazarain <gfc@altern.org>
Cc: Davide Libenzi <davidel@xmailserver.org>,
	Mike Galbraith <efault@gmx.de>, <linux-kernel@vger.kernel.org>
Subject: Re: [patch] sched-2.6.0-test1-G3, interactivity changes, audio latency
Date: Sun, 27 Jul 2003 12:26:56 +0200 (CEST)	[thread overview]
Message-ID: <Pine.LNX.4.44.0307271151180.9853-100000@localhost.localdomain> (raw)
In-Reply-To: <VRC7KGZX0573CW1TPN65C3Y312IC.3f22a7b7@monpc>


On Sat, 26 Jul 2003, Guillaume Chazarain wrote:

> BTW, with your nanosecond resolution, mplayer is also max interactive.

good.

> Don't you find it strange to need a nanosecond resolution to evaluate a
> simple integer in a [-5, 5] range?

no, i dont find it strange, as the -5..5 integer range is only the end
result. What we really want is an accurate sleep average, the integral of
sleep times done over the last N seconds. Given that tasks can schedule at
very high frequencies these days, this needs accurate measurements. I used
to hope that a 1 msec sampling frequency would to be enough for this, but
when we fix the statistics cornercase you mention, another cornercase pops
up. And it's not _that_ hard to use the cycle counter and still have a
reasonably fast algorithm, anyway.

	Ingo


  parent reply	other threads:[~2003-07-27 10:19 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-07-26 16:09 Guillaume Chazarain
2003-07-27  9:31 ` Mike Galbraith
2003-07-27 10:26 ` Ingo Molnar [this message]
  -- strict thread matches above, loose matches on Subject: below --
2003-07-25 19:59 Ingo Molnar
2003-07-25 22:58 ` Felipe Alfaro Solana
2003-07-25 23:30 ` Con Kolivas

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