Messages in this thread | | | Subject | Re: Low latency I/O scheduling | From | Maxim Levitsky <> | Date | Sat, 20 Jun 2009 00:26:27 +0300 |
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On Mon, 2009-06-08 at 19:40 +0200, Corrado Zoccolo wrote: > Hi, > sometime ago on the mailing list, the issue of too high latencies > introduced by I/O scheduling was raised. > I've done some study, and identified a way to improve on workloads > that have >1 random readers.
You can say that again....
While there was all the fuzz about CPU scheduler, just doing some heavy IO can literally stall the system for minutes (and I am not talking about swap trashing, I have here 2 GB, and about 400 MB used)
Sometimes it goes so far, that I have to suspend the offending process. I mostly compile stuff, buf file copies have even worse effect.
I tried CFQ, AS, and didn't see much difference (but ionice on CFQ really helps)
Best regards, Maxim Levitsky
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