From: Nick Piggin <nickpiggin@yahoo.com.au>
To: "linux-os (Dick Johnson)" <linux-os@analogic.com>
Cc: Brian Twichell <tbrian@us.ibm.com>,
linux-kernel@vger.kernel.org, mbligh@mbligh.org,
slpratt@us.ibm.com, anton@samba.org
Subject: Re: Database regression due to scheduler changes ?
Date: Tue, 08 Nov 2005 14:54:39 +1100 [thread overview]
Message-ID: <4370217F.3090807@yahoo.com.au> (raw)
In-Reply-To: <Pine.LNX.4.61.0511071745020.28676@chaos.analogic.com>
linux-os (Dick Johnson) wrote:
>
> Can you change sched_yield() to usleep(1) or usleep(0) and see if
> that works. I found that in recent kernels sched_yield() just seems
> to spin (may not actually spin, but seems to with a high CPU usage).
>
I've told you that it *does* spin and always has. Even with 2.4
kernels. In fact, it is *specified* to spin, anything else would
be a bug.
Caveat: it also yields the CPU, but only if there is another
runnable task with a higher priority (which is meaningless
between SCHED_OTHER tasks, though we try to do something sane
there too).
Secondly, Brian actually pinpointed the source of the
regression and it is not sched_yield(), nor has sched_yield
changed since the regression. So wouldn't this just be a wild
goose chase.
Nick
--
SUSE Labs, Novell Inc.
Send instant messages to your online friends http://au.messenger.yahoo.com
next prev parent reply other threads:[~2005-11-08 3:52 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-11-07 22:17 Database regression due to scheduler changes ? Brian Twichell
2005-11-07 22:35 ` David Lang
2005-11-07 23:06 ` Brian Twichell
2005-11-08 0:51 ` Nick Piggin
2005-11-08 1:15 ` Anton Blanchard
2005-11-08 1:34 ` Martin J. Bligh
2005-11-08 1:46 ` Nick Piggin
2005-11-08 1:48 ` Nick Piggin
2005-11-08 1:58 ` Martin J. Bligh
2005-11-08 2:04 ` David Lang
2005-11-08 2:12 ` Martin J. Bligh
2005-11-08 2:15 ` Nick Piggin
2005-11-09 5:03 ` Brian Twichell
[not found] ` <43718DFE.3040600@yahoo.com.au>
2005-11-14 23:03 ` Brian Twichell
2005-11-08 2:31 ` Byron Stanoszek
2005-11-07 22:47 ` linux-os (Dick Johnson)
2005-11-08 3:54 ` Nick Piggin [this message]
[not found] <43715361.3070802@us.ibm.com>
2005-11-09 2:14 ` Andrew Theurer
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