From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Pedro Larroy <piotr@larroy.com>
Cc: Andrew Morton <akpm@osdl.org>, linux-kernel@vger.kernel.org
Subject: Re: CFQ iosched praise: good perfomance and better latency
Date: Mon, 19 Apr 2004 21:53:31 +1000 [thread overview]
Message-ID: <4083BDBB.2050904@yahoo.com.au> (raw)
In-Reply-To: <20040419113243.GA18042@larroy.com>
Pedro Larroy wrote:
> On Mon, Apr 19, 2004 at 04:12:56PM +1000, Nick Piggin wrote:
>>Well I think Pedro actually means *seconds*, not ms. The URL
>>shows AS peaks at nearly 10 seconds latency, and CFQ over 2s.
>
>
> Yes, I meant seconds, my mistake. I will be testing elevator=noop this
> evening.
>
That would be interesting.
>
>>It really seems like a raid problem though, because latency
>>measured at the individual devices is under 250ms for AS.
>
>
> Probably. But I was surprised to find that bonnie gave similar results
> with CFQ and with AS when benchmarking the swraid5.
I haven't used bonnie, but I think it is single threaded, isn't
it? If that is the case, then the IO scheduler will make little
or no difference, so your result is not surprising.
next prev parent reply other threads:[~2004-04-19 11:53 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-04-19 0:56 CFQ iosched praise: good perfomance and better latency Pedro Larroy
2004-04-19 5:10 ` Nick Piggin
2004-04-19 5:57 ` Andrew Morton
2004-04-19 6:12 ` Nick Piggin
2004-04-19 11:32 ` Pedro Larroy
2004-04-19 11:53 ` Nick Piggin [this message]
2004-04-19 23:59 ` Pedro Larroy
2004-04-19 13:27 ` Daniel Pittman
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