From: Jens Axboe <jens.axboe@oracle.com>
To: Edward Falk <efalk@google.com>
Cc: linux-kernel@vger.kernel.org, Andrew Morton <akpm@osdl.org>
Subject: Re: [PATCH] Introduce block I/O performance histograms
Date: Thu, 16 Nov 2006 07:58:47 +0100 [thread overview]
Message-ID: <20061116065846.GE32394@kernel.dk> (raw)
In-Reply-To: <455BD7E8.9020303@google.com>
On Wed, Nov 15 2006, Edward Falk wrote:
> This patch introduces performance histogram record keeping for block
> I/O, used for performance tuning. It is turned off by default.
>
> When turned on, you simply do something like:
>
> # cat /sys/block/sda/read_request_histo
> rows = bytes columns = ms
> 10 20 50 100 200 500 1000 2000
> 2048 5 0 0 0 0 0 0 0
> 4096 0 0 0 0 0 0 0 0
> 8192 17231 135 41 10 0 0 0 0
> 16384 4400 24 6 2 0 0 0 0
> 32768 2897 34 4 4 0 0 0 0
> 65536 7089 87 5 1 2 0 0 0
I don't see the point at all for including this piece of code in the
kernel. You can do the same from user space. Your help entry said it
even grows the kernel size about 21k, that's pretty nasty.
So NAK.
--
Jens Axboe
next prev parent reply other threads:[~2006-11-16 6:59 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-11-16 3:15 [PATCH] Introduce block I/O performance histograms Edward Falk
2006-11-16 6:58 ` Jens Axboe [this message]
2006-11-16 20:01 ` Edward Falk
2006-11-16 20:21 ` Jens Axboe
2006-11-16 20:01 ` Greg KH
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