Messages in this thread |  | | Date | Mon, 16 Jun 2008 18:01:11 -0700 (PDT) | From | Divyesh Shah <> | Subject | Re: [BUGFIX][RESEND] Fix the starving writes bug in the anticipatory IO scheduler |
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On Mon, 16 Jun 2008, Nick Piggin wrote:
> Well, thanks for the report and test case. I'm a bit out of the > loop when it comes to IO scheduling these days, however the fix > seems good to me. > > Does google still use AS scheduling? This doesn't introduce any > performance regressions that you can tell?
Yes we use AS scheduler. Benchmarking results on workloads have shown that AS does as good a job (and better in some cases) as CFQ. When there is a single thread reading/writing to disk, AS performs as well as CFQ. With multiple threads doing IO such that there are a lot of outstanding requests, CFQ performs worse than AS in terms of throughput.
-Divyesh.
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