From: Ondrej Zary <linux@rainbow-software.org>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>,
Grant Coady <grant_lkml@dodo.com.au>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Odd IDE performance drop 2.4 vs 2.6?
Date: Wed, 15 Jun 2005 21:15:41 +0200 [thread overview]
Message-ID: <42B07E5D.9070004@rainbow-software.org> (raw)
In-Reply-To: <1118675343.13773.1.camel@localhost.localdomain>
Alan Cox wrote:
> On Llu, 2005-06-13 at 15:06, Nick Piggin wrote:
>
>>>Make sure you have pre-empt disabled and the antcipatory I/O scheduler
>>>disabled.
>>>
>>
>>I don't think that those could explain it.
>
>
> Try it and see. The anticipatory I/O scheduler does horrible things to
> my IDE streaming performance numbers and to swap performance. It tries
> to merge I/O by delaying it which is deeply ungood when it comes to IDE
> streaming even if its good for general I/O.
Now I've tested it with preempt disabled and nothing has changed. When
fiddling around with hdparm, I got about 16MB/s max. with 2.6.12-rc5.
With 2.4.31, I got about 21MB/s when just the DMA was enabled
(read-ahead and multcount set to 0 - changing them does not make almost
any difference).
--
Ondrej Zary
next prev parent reply other threads:[~2005-06-15 19:15 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-06-13 4:03 Odd IDE performance drop 2.4 vs 2.6? Grant Coady
2005-06-13 10:43 ` Ondrej Zary
2005-06-13 13:39 ` Alan Cox
2005-06-13 14:06 ` Nick Piggin
2005-06-13 15:09 ` Alan Cox
2005-06-13 17:01 ` Ondrej Zary
2005-06-13 20:25 ` Jens Axboe
2005-06-14 2:20 ` Nick Piggin
2005-06-15 19:15 ` Ondrej Zary [this message]
2005-06-17 12:40 ` Alan Cox
2005-06-17 13:43 ` Ondrej Zary
2005-06-13 18:13 ` Grant Coady
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