Messages in this thread | | | Date | Fri, 8 May 2009 12:01:19 -0700 | From | Andrew Morton <> | Subject | Re: 2.6.30-rc deadline scheduler performance regression for iozone over NFS |
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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.
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