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From: Grant Coady <grant_lkml@dodo.com.au>
To: Mark Lord <liml@rtr.ca>
Cc: Jens Axboe <axboe@suse.de>, Ondrej Zary <linux@rainbow-software.org>,
       =?ISO-8859-1?Q?=20Andr=E9?= Tomt <andre@tomt.net>,
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       "'Linus Torvalds'" <torvalds@osdl.org>, linux-ide@vger.kernel.org,
       linux-kernel@vger.kernel.org
Subject: Re: [git patches] IDE update
Date: Fri, 08 Jul 2005 10:06:43 +1000
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On Thu, 07 Jul 2005 18:32:52 -0400, Mark Lord <liml@rtr.ca> wrote:
>
>hdparm can also use O_DIRECT for the -t timing test.

I've not been able to get dual channel I/O speed faster than single 
interface speed, either as 'md' RAID0 or simultaneous reading or 
writing done the other day:

Time to write or read 500MB file:

>summary		2.4.31-hf1	2.6.12.2
>boxen \ time ->	 w 	 r	 w	 r
>---------------	----	----	----	----
...
>peetoo			33	20	26.5	22
>(simultaneuous		57	37.5	52	38.5)

MB/s		2.4.31-hf1	2.6.12.2
		w	r	w	r
single		15	25	19	23
dual		17.5	27	19	26

These timings show very little happening in parallel, is that normal?

Thanks,
--Grant.