Messages in this thread | | | Subject | Re: IO scheduler based IO controller V10 | From | Mike Galbraith <> | Date | Mon, 28 Sep 2009 20:24:57 +0200 |
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On Mon, 2009-09-28 at 13:48 -0400, Vivek Goyal wrote:
> Hmm.., so close to 25% reduction on average in completion time of konsole. > But this is in presece of writer. Does this help even in presence of 1 or > more sequential readers going?
Dunno, I've only tested sequential writer.
> So here latency seems to be coming from three sources. > > - Wait in CFQ before request is dispatched (only in case of competing seq readers). > - seek latencies > - latencies because of bigger requests are already dispatched to disk. > > So limiting the size of request will help with third factor but not with first > two factors and here seek latencies seem to be the biggest contributor.
Yeah, seek latency seems to dominate.
-Mike
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