Messages in this thread |  | | | From | Jeff Moyer <> | | Subject | Re: tiobench read 50% regression with 2.6.30-rc1 | | Date | Wed, 15 Apr 2009 07:25:39 -0400 |
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Jens Axboe <jens.axboe@oracle.com> writes:
> On Wed, Apr 15 2009, Jeff Moyer wrote: >> I tested this using iozone to read a file from an NFS client. 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. I >> included numbers for the deadline scheduler as well for comparison. >> >> v2.6.29 >> >> nfsd's | 1 | 2 | 4 | 8 >> --------+---------------+-------+------ >> cfq | 91356 | 66391 | 61942 | 51674 >> deadline| 43207 | 67436 | 96289 | 107784 >> >> 2.6.30-rc1 >> >> nfsd's | 1 | 2 | 4 | 8 >> --------+---------------+-------+------ >> cfq | 43127 | 22354 | 20858 | 21179 >> deadline| 43732 | 68059 | 76659 | 83231 >> >> 2.6.30-rc1 + cfq fix >> >> nfsd's | 1 | 2 | 4 | 8 >> --------+-----------------+-------+------ >> cfq | 114602 | 102280 | 43479 | 43160 >> >> As you can see, for 1 and 2 threads, the patch *really* helps out. We >> still don't get back the performance for 4 and 8 nfsd threads, though. >> It's interesting to note that the deadline scheduler regresses for 4 and >> 8 threads, as well. I think we've still got some digging to do. > > Wow, that does indeed look pretty good!
Please don't lose the later part of the message, which is that both CFQ and deadline regress for 4 and 8 threads when moving from 2.6.29 to 2.6.30-rc1! There have been way too many changes to keep track of in this area recently, and I'd like to get some confidence that we understand the performance implications of them.
>> I'll try the cfq close cooperator patches next. > > I have a pending update on the coop patch that isn't pushed out yet, I > hope to have it finalized and tested later today. Hopefully, with that, > we should be able to maintain > 100Mb/sec for 4 and 8 threads.
OK, please let me know when and where this is available and I'll give it a try.
Cheers, Jeff
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