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Message-ID: <1321884075.20742.5.camel@frodo>
Date: Mon, 21 Nov 2011 09:01:15 -0500
From: Steven Rostedt <rostedt@...dmis.org>
To: Wu Fengguang <fengguang.wu@...el.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
Linux Memory Management List <linux-mm@...ck.org>,
linux-fsdevel@...r.kernel.org, Ingo Molnar <mingo@...e.hu>,
Jens Axboe <jens.axboe@...cle.com>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Rik van Riel <riel@...hat.com>,
LKML <linux-kernel@...r.kernel.org>,
Andi Kleen <andi@...stfloor.org>
Subject: Re: [PATCH 6/8] readahead: add debug tracing event
On Mon, 2011-11-21 at 17:18 +0800, Wu Fengguang wrote:
> plain text document attachment (readahead-tracer.patch)
> This is very useful for verifying whether the algorithms are working
> to our expectaions.
>
> Example output:
>
> # echo 1 > /debug/tracing/events/vfs/readahead/enable
> # cp test-file /dev/null
> # cat /debug/tracing/trace # trimmed output
> readahead-initial(dev=0:15, ino=100177, req=0+2, ra=0+4-2, async=0) = 4
> readahead-subsequent(dev=0:15, ino=100177, req=2+2, ra=4+8-8, async=1) = 8
> readahead-subsequent(dev=0:15, ino=100177, req=4+2, ra=12+16-16, async=1) = 16
> readahead-subsequent(dev=0:15, ino=100177, req=12+2, ra=28+32-32, async=1) = 32
> readahead-subsequent(dev=0:15, ino=100177, req=28+2, ra=60+60-60, async=1) = 24
> readahead-subsequent(dev=0:15, ino=100177, req=60+2, ra=120+60-60, async=1) = 0
>
> CC: Ingo Molnar <mingo@...e.hu>
> CC: Jens Axboe <jens.axboe@...cle.com>
> CC: Steven Rostedt <rostedt@...dmis.org>
Acked-by: Steven Rostedt <rostedt@...dmis.org>
-- Steve
> CC: Peter Zijlstra <a.p.zijlstra@...llo.nl>
> Acked-by: Rik van Riel <riel@...hat.com>
> Signed-off-by: Wu Fengguang <fengguang.wu@...el.com>
--
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