From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Thomas Pilarski <thomas.pi@arcor.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Mike Galbraith <efault@gmx.de>,
Gregory Haskins <ghaskins@novell.com>,
bugme-daemon@bugzilla.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [Bugme-new] [Bug 12562] New: High overhead while switching or synchronizing threads on different cores
Date: Thu, 29 Jan 2009 10:07:28 +0100 [thread overview]
Message-ID: <1233220048.7835.19.camel@twins> (raw)
In-Reply-To: <1233181507.6988.14.camel@bugs-laptop>
On Wed, 2009-01-28 at 23:25 +0100, Thomas Pilarski wrote:
> Am Mittwoch, den 28.01.2009, 12:56 -0800 schrieb Andrew Morton:
>
> > (There's testcase code in the bugzilla report)
> >
> > (Seems to be a regression)
>
> There is a regression, because of the improved cpu switching. The
> problem exists in every kernel.
This is a contradiction in terms - twice.
If it is a regression, then clearly things haven't improved.
If it is a regression, state clearly when it worked last. If it never
worked, it cannot be a regression.
> I takes a lot of time to switch between the threads, when they are
> executed on different cores.
> Perhaps of the big buffer size of 512KB?
Of course, pushing 512kb to another cpu means lots and lots of cache
misses.
next prev parent reply other threads:[~2009-01-29 9:07 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <bug-12562-10286@http.bugzilla.kernel.org/>
2009-01-28 20:56 ` [Bugme-new] [Bug 12562] New: High overhead while switching or synchronizing threads on different cores Andrew Morton
2009-01-28 22:15 ` Peter Zijlstra
2009-01-28 22:25 ` Thomas Pilarski
2009-01-29 9:07 ` Peter Zijlstra [this message]
2009-01-29 10:12 ` Thomas Pilarski
2009-01-29 10:24 ` Thomas Pilarski
2009-01-29 10:31 ` Peter Zijlstra
2009-01-29 11:37 ` Peter Zijlstra
2009-01-29 14:05 ` Thomas Pilarski
2009-01-30 7:57 ` Mike Galbraith
2009-02-02 7:43 ` Thomas Pilarski
2009-02-02 8:19 ` Peter Zijlstra
2009-02-02 8:33 ` Thomas Pilarski
2009-02-02 8:52 ` Mike Galbraith
2009-02-02 8:55 ` Peter Zijlstra
2009-02-02 12:15 ` Peter Zijlstra
2009-02-02 18:29 ` Michael Kerrisk
2009-02-02 18:35 ` Peter Zijlstra
2009-02-03 4:55 ` Mike Galbraith
2009-02-03 3:56 ` Valdis.Kletnieks
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