Messages in this thread | ![/](/images/icornerl.gif) | | Date | Sat, 02 Apr 2005 12:12:24 +1000 | From | Nick Piggin <> | Subject | Re: Industry db benchmark result on recent 2.6 kernels |
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Chen, Kenneth W wrote: > Ingo Molnar wrote on Thursday, March 31, 2005 8:52 PM > >>the current defaults for cache_hot_time are 10 msec for NUMA domains, >>and 2.5 msec for SMP domains. Clearly too low for CPUs with 9MB cache. >>Are you increasing cache_hot_time in your experiment? If that solves >>most of the problem that would be an easy thing to fix for 2.6.12. > > > > Chen, Kenneth W wrote on Thursday, March 31, 2005 9:15 PM > >>Yes, we are increasing the number in our experiments. It's in the queue >>and I should have a result soon. > > > Hot of the press: bumping up cache_hot_time to 10ms on our db setup brings > 2.6.11 performance on par with 2.6.9. Theory confirmed. >
OK, that's good. I'll look at whether we can easily use Ingo's tool on the SMP domain only, to avoid the large O(n^2). That might be an acceptable short term solution for 2.6.12.
If you get a chance to also look at those block layer patches that would be good - if they give you a nice improvement, that would justify getting them into -mm.
-- SUSE Labs, Novell Inc.
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