Message-ID: <4191F9E6.9010709@gmx.de>
Date: Wed, 10 Nov 2004 12:22:14 +0100
From: "Prakash K. Cheemplavam" <prakashkc@gmx.de>
User-Agent: Mozilla Thunderbird 0.9 (X11/20041109)
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To: Robert Love <rml@novell.com>
CC: Pedro Larroy <piotr@larroy.com>, linux-kernel@vger.kernel.org
Subject: Re: Ideas for a new io scheduler for desktop
References: <20041110013235.GA13691@larroy.com> <1100051419.18601.105.camel@localhost>
In-Reply-To: <1100051419.18601.105.camel@localhost>
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Robert Love wrote:
> On Wed, 2004-11-10 at 02:32 +0100, Pedro Larroy wrote:
> 
> 
>>I think that a new io-scheduler that gave priority to bursty access to
>>block devices would be interesting for desktop and workstation use, and
>>even for some servers.
>>
>>I'm often waiting for graphical aplications, vim, mutt, and almost every
>>program to which I have to interact with because they are blocked
>>waiting for just a few blocks of IO that won't get served fast just
>>because there's a single process hog that's provoking that high latency.

[snip]

> 
> What you are seeing is the affect of read requests being synchronous,
> and thus the pain of read latency, and write requests to one part of the
> disk starving other requests.
> 
> Have you tried the new 2.6 I/O schedulers?  They should prevent this
> problem.
> 
> If you are using 2.6, then your problem might not lie with the I/O
> scheduler.  Read request deadlines are very low in both the deadline and
> anticipatory I/O scheduler.

BTW, I saw the same problem, though not with reading, but with writing 
to disk. See thread (well nobody answered to it yet):

[2.6.10-rc1 and prev] System unuseable while writing to disk

It really takes away the fun... :(

Prakash

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