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Date: Fri, 06 Aug 2004 19:44:47 +0100
From: Paulo Marques <pmarques@grupopie.com>
Organization: Grupo PIE
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To: Thomas Charbonnel <thomas@undata.org>
Cc: Ingo Molnar <mingo@redhat.com>, Shane Shrybman <shrybman@aei.ca>,
       linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [patch] voluntary-preempt-2.6.8-rc2-O2
References: <1091459297.2573.10.camel@mars>	 <Pine.LNX.4.58.0408031019090.20420@devserv.devel.redhat.com> <1091815684.7586.28.camel@localhost>
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Thomas Charbonnel wrote:
>....
> While accessing the file system (this one is very frequent):
> 
> Aug  2 15:32:24 satellite (bash/5298): 1095us non-preemptible critical
> section violated 1000 us preempt threshold starting at
> search_by_key+0x120/0x1140 and ending at voluntary_resched+0x1a/0x70
> Aug  2 15:32:24 satellite [<c010574e>] dump_stack+0x1e/0x30
> Aug  2 15:32:24 satellite [<c01171a6>] touch_preempt_timing+0x36/0x50
> Aug  2 15:32:24 satellite [<c042856a>] voluntary_resched+0x1a/0x70
> Aug  2 15:32:24 satellite [<c0158c44>] __getblk+0x44/0x70
> Aug  2 15:32:24 satellite [<c01ae348>] search_by_key+0x78/0x1140
> Aug  2 15:32:24 satellite [<c01af4bc>]
> search_for_position_by_key+0xac/0x3f0
> Aug  2 15:32:24 satellite [<c019e0c4>]
> reiserfs_allocate_blocks_for_region+0x354/0x15b0
> Aug  2 15:32:24 satellite [<c01a0c4c>] reiserfs_file_write+0x61c/0x8d0
                                          ^^^^^^^^
I remember some discussion on a "voluntary preempt" thread, about 
reiserfs being bad for latency.

You might search the archives for this, but as far as I remember, ext3 
was a better alternative, latency-wise.

-- 
Paulo Marques - www.grupopie.com
"In a world without walls and fences who needs windows and gates?"