Messages in this thread |  | | | Date | Mon, 11 May 2009 10:14:15 +0200 | | From | Jens Axboe <> | | Subject | Re: 2.6.30-rc deadline scheduler performance regression for iozone over NFS |
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On Fri, May 08 2009, Andrew Morton wrote: > On Thu, 23 Apr 2009 10:01:58 -0400 > Jeff Moyer <jmoyer@redhat.com> wrote: > > > Hi, > > > > I've been working on CFQ improvements for interleaved I/Os between > > processes, and noticed a regression in performance when using the > > deadline I/O scheduler. The test uses a server configured with a cciss > > array and 1Gb/s ethernet. > > > > The iozone command line was: > > iozone -s 2000000 -r 64 -f /mnt/test/testfile -i 1 -w > > > > The numbers in the nfsd's row represent the number of nfsd "threads". > > These numbers (in MB/s) represent the average of 5 runs. > > > > v2.6.29 > > > > nfsd's | 1 | 2 | 4 | 8 > > --------+---------------+-------+------ > > deadline| 43207 | 67436 | 96289 | 107590 > > > > 2.6.30-rc1 > > > > nfsd's | 1 | 2 | 4 | 8 > > --------+---------------+-------+------ > > deadline| 43732 | 68059 | 76659 | 83231 > > > > 2.6.30-rc3.block-for-linus > > > > nfsd's | 1 | 2 | 4 | 8 > > --------+---------------+-------+------ > > deadline| 46102 | 71151 | 83120 | 82330 > > > > > > Notice the drop for 4 and 8 threads. It may be worth noting that the > > default number of NFSD threads is 8. > > > > I guess we should ask Rafael to add this to the post-2.6.29 regression > list.
I agree. It'd be nice to bisect this one down, I'm guessing some mm change has caused this writeout regression.
-- Jens Axboe
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