From: Mike Galbraith <efault@gmx.de>
To: Bill Davidsen <davidsen@tmr.com>
Cc: Olof Johansson <olof@lixom.net>, Willy Tarreau <w@1wt.eu>,
linux-kernel@vger.kernel.org,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Ingo Molnar <mingo@elte.hu>
Subject: Re: Scheduler(?) regression from 2.6.22 to 2.6.24 for short-lived threads
Date: Tue, 12 Feb 2008 05:30:35 +0100 [thread overview]
Message-ID: <1202790635.4165.43.camel@homer.simson.net> (raw)
In-Reply-To: <47B0C1E8.2050809@tmr.com>
On Mon, 2008-02-11 at 16:45 -0500, Bill Davidsen wrote:
> I think the moving to another CPU gets really dependent on the CPU type.
> On a P4+HT the caches are shared, and moving costs almost nothing for
> cache hits, while on CPUs which have other cache layouts the migration
> cost is higher. Obviously multi-core should be cheaper than
> multi-socket, by avoiding using the system memory bus, but it still can
> get ugly.
>
> I have an IPC test around which showed that, it ran like hell on HT, and
> progressively worse as cache because less shared. I wonder why the
> latest git works so much better?
Yes, I'm wondering the same. With latest git, ~400 usec work units
suffice to achieve overlap (on my P4/HT), whereas all other kernels
tested require several milliseconds.
-Mike
next prev parent reply other threads:[~2008-02-12 4:30 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-02-09 0:04 Scheduler(?) regression from 2.6.22 to 2.6.24 for short-lived threads Olof Johansson
2008-02-09 0:08 ` Ingo Molnar
2008-02-09 0:32 ` Olof Johansson
2008-02-09 7:58 ` Mike Galbraith
2008-02-09 8:03 ` Willy Tarreau
2008-02-09 10:58 ` Mike Galbraith
2008-02-09 11:40 ` Willy Tarreau
2008-02-09 13:37 ` Mike Galbraith
2008-02-09 16:19 ` Willy Tarreau
2008-02-09 17:33 ` Mike Galbraith
2008-02-10 5:29 ` Olof Johansson
2008-02-10 6:15 ` Willy Tarreau
2008-02-10 7:00 ` Olof Johansson
2008-02-10 7:58 ` Willy Tarreau
2008-02-11 8:15 ` Mike Galbraith
2008-02-11 17:26 ` Olof Johansson
2008-02-11 19:58 ` Mike Galbraith
2008-02-11 20:31 ` Olof Johansson
2008-02-12 9:23 ` Mike Galbraith
2008-02-13 5:49 ` Mike Galbraith
2008-02-11 21:45 ` Bill Davidsen
2008-02-12 4:30 ` Mike Galbraith [this message]
[not found] <fa.6N2dhyJ1cmBqiuFKgCaYfwduM+0@ifi.uio.no>
2008-02-09 1:49 ` Robert Hancock
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