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Date: Tue, 6 May 2008 20:59:30 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>, Matthew Wilcox <matthew@wil.cx>,
       LKML <linux-kernel@vger.kernel.org>,
       Alexander Viro <viro@ftp.linux.org.uk>,
       Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: AIM7 40% regression with 2.6.26-rc1
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On Wed, 07 May 2008 11:41:52 +0800 "Zhang, Yanmin" <yanmin_zhang@linux.intel.com> wrote:

> As system idle is more than 50%, so the schedule/schedule_timeout caller is important
> information.
> 1) lock_kernel causes most schedule/schedule_timeout;
> 2) When lock_kernel calls down, then __down, __down calls ___schedule_timeout for
> lots of times in a loop;

Really?  Are you sure?  That would imply that we keep on waking up tasks
which then fail to acquire the lock.  But the code pretty plainly doesn't
do that.

Odd.

> 3) Caller of lcok_kernel are sys_fcntl/vfs_ioctl/tty_release/chrdev_open.

Still :(