Messages in this thread | | | Subject | Re: [RFC] Block IO Controller V2 - some results | From | "Alan D. Brunelle" <> | Date | Tue, 17 Nov 2009 11:45:00 -0500 |
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On Tue, 2009-11-17 at 17:17 +0100, Corrado Zoccolo wrote: > Hi Vivek, > the performance drop reported by Alan was my main concern about your > approach. Probably you should mention/document somewhere that when the > number of groups is too large, there is large decrease in random read > performance. > > However, we can check few things: > * is this kernel built with HZ < 1000? The smallest idle CFQ will do > is given by 2/HZ, so running with a small HZ will increase the impact > of idling.
FYI:
CONFIG_NO_HZ=y CONFIG_HZ_1000=y CONFIG_HZ=1000
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