Messages in this thread | | | From | "Chen, Kenneth W" <> | Subject | RE: [patch] sched: auto-tune migration costs [was: Re: Industry db benchmark result on recent 2.6 kernels] | Date | Tue, 5 Apr 2005 20:33:14 -0700 |
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Ingo Molnar wrote on Monday, April 04, 2005 8:05 PM > > latest patch attached. Changes: > > - stabilized calibration even more, by using cache flushing > instructions to generate a predictable working set. The cache > flushing itself is not timed, it is used to create quiescent > cache state. > > I only guessed the ia64 version - e.g. i didnt know what 'type' > argument to pass to ia64_sal_cache_flush() to get a d/cache > flush+invalidate.
It is preferable to use a ia64_pal_cache_flush instead of SAL call. But it hangs the machine with that pal call. I will look at it tomorrow. The type argument for sal_cache_flush is: 1 for icache, 2 for dcache, and 3 for i+d.
> - due to more stable results, reduced ITERATIONS from 3 to 2 - this > should further speed up calibration. > > tested on x86, the calibration results look ok there.
Calibration result on ia64 (1.5 GHz, 9 MB), somewhat smaller in this version compare to earlier estimate of 10.4ms. The optimal setting found by a db workload is around 16 ms.
--------------------- | migration cost matrix (max_cache_size: 9437184, cpu: -1 MHz):
--------------------- [00] [01] [02] [03] [00]: - 9.3(0) 9.3(0) 9.3(0) [01]: 9.3(0) - 9.3(0) 9.3(0) [02]: 9.3(0) 9.3(0) - 9.3(0) [03]: 9.3(0) 9.3(0) 9.3(0) - -------------------------------- | cacheflush times [1]: 9.3 (9329800) | calibration delay: 16 seconds --------------------------------
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