From: Jens Axboe <axboe@kernel.dk>
To: Shaohua Li <shaohua.li@intel.com>
Cc: lkml <linux-kernel@vger.kernel.org>
Subject: Re: [patch 2/2]block: recursive merge requests
Date: Fri, 16 Dec 2011 13:59:07 +0100 [thread overview]
Message-ID: <4EEB409B.3070004@kernel.dk> (raw)
In-Reply-To: <1324000363.22361.453.camel@sli10-conroe>
On 2011-12-16 02:52, Shaohua Li wrote:
> In my workload, thread 1 accesses a, a+2, ..., thread 2 accesses a+1,
> a+3,.... When the requests are flushed to queue, a and a+1 are merged
> to (a, a+1), a+2 and a+3 too to (a+2, a+3), but (a, a+1) and (a+2, a+3)
> aren't merged.
> With recursive merge below, the workload throughput gets improved 20%
> and context switch drops 60%.
Interesting, I didn't consider that corner case. Hard to argue with the
numbers, this might positively impact apps using posix aio for instance.
Applied to for-3.3/core.
--
Jens Axboe
next prev parent reply other threads:[~2011-12-16 12:59 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-16 1:52 [patch 2/2]block: recursive merge requests Shaohua Li
2011-12-16 12:59 ` Jens Axboe [this message]
2011-12-16 19:34 ` Christoph Hellwig
2011-12-16 20:16 ` Jens Axboe
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