Messages in this thread |  | | | Date | Thu, 12 Nov 2009 18:29:41 +0100 | | From | Jan Kara <> | | Subject | Re: Performance regression in IO scheduler still there |
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On Wed 11-11-09 12:43:30, Jeff Moyer wrote: > Jan Kara <jack@suse.cz> writes: > > > Sadly, I don't see the improvement you can see :(. The numbers are the > > same regardless low_latency set to 0: > > 2.6.32-rc5 low_latency = 0: > > 37.39 36.43 36.51 -> 36.776667 0.434920 > > But my testing environment is a plain SATA drive so that probably > > explains the difference... > > I just retested (10 runs for each kernel) on a SATA disk with no NCQ > support and I could not see a difference. I'll try to dig up a disk > that support NCQ. Is that what you're using for testing? I don't think I am. How do I find out?
> 2.6.29 2.6.32-rc6,low_latency=0 > ---------------------------------- > Average: 34.6648 34.4475 > Pop.Std.Dev.: 0.55523 0.21981 Hmm, strange. Miklos Szeredi tried tiobench on his machine and he also saw the regression. I'll try to think what could make the difference.
Honza -- Jan Kara <jack@suse.cz> SUSE Labs, CR
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