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SubjectRe: Industry db benchmark result on recent 2.6 kernels
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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