Re: [ak@suse.de: Re: iosched: impact of streaming read on read-many-files]

From: Andrea Arcangeli (andrea@suse.de)
Date: Sun Feb 23 2003 - 10:34:39 EST


On Fri, Feb 21, 2003 at 11:07:16PM -0800, Andrew Morton wrote:
> request within ten milliseconds is an impossibility. Attempting to
> achieve it will result in something which seeks all over the place.

This is called SFQ, or CFQ with 0 dispatch queue level and it works
fine (given a fixed amount of tasks doing I/O). You still don't
understand you don't care about throughput and seeks if you only need to
read 1 block with the max fairness and you don't mind to read another
block within 1 second. seeking is the last problem here, waiting more
than 1 second is the only problem here.

Andrea
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