Messages in this thread | | | Date | Fri, 16 Sep 2011 22:50:17 +0800 | From | Tao Ma <> | Subject | Re: [patch]cfq-iosched: delete deep seeky queue idle logic |
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On 09/16/2011 10:08 PM, Christoph Hellwig wrote: > On Fri, Sep 16, 2011 at 05:54:51PM +0800, Tao Ma wrote: >> This year's FAST has a paper named "A Scheduling Framework That Makes >> Any Disk Schedulers Non-Work-Conserving Solely Based on Request >> Characteristics". It has described this situation and suggests a new >> scheduler named "stream scheduler" to resolve this. But I am not sure >> whether CFQ can work like that or not. > > As usual I suspect the best thing is to just use noop for these kinds of > cases. E.g. when you use xfs with the filestreams options you'll get > patterns pretty similar to that in the initial post - that is > intentional as it is generally use to place them into different areas > of a complex RAID array. Any scheduler "smarts" will just help to break these > I/O streams. yeah, actually the paper does show that the performance of cfq is worse than noop in this case. ;) See section 3.4 if you are interested.
Thanks Tao
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