Re: [RFC PATCH 0/8][Sorted-buddy] mm: Linux VM Infrastructure to support Memory Power Management

["Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>]

On 11/09/2012 10:13 PM, Srivatsa S. Bhat wrote:
> On 11/09/2012 10:04 PM, Srivatsa S. Bhat wrote:
>> On 11/09/2012 09:43 PM, Dave Hansen wrote:
>>> On 11/09/2012 07:23 AM, Srivatsa S. Bhat wrote:
>>>> FWIW, kernbench is actually (and surprisingly) showing a slight performance
>>>> *improvement* with this patchset, over vanilla 3.7-rc3, as I mentioned in
>>>> my other email to Dave.
>>>>
>>>> https://lkml.org/lkml/2012/11/7/428
>>>>
>>>> I don't think I can dismiss it as an experimental error, because I am seeing
>>>> those results consistently.. I'm trying to find out what's behind that.
>>>
>>> The only numbers in that link are in the date. :)  Let's see the
>>> numbers, please.
>>>
>>
>> Sure :) The reason I didn't post the numbers very eagerly was that I didn't
>> want it to look ridiculous if it later turned out to be really an error in the
>> experiment ;) But since I have seen it happening consistently I think I can
>> post the numbers here with some non-zero confidence.
>>
>>> If you really have performance improvement to the memory allocator (or
>>> something else) here, then surely it can be pared out of your patches
>>> and merged quickly by itself.  Those kinds of optimizations are hard to
>>> come by!
>>>
>>
>> :-)
>>
>> Anyway, here it goes:
>>
>> Test setup:
>> ----------
>> x86 2-socket quad-core machine. (CONFIG_NUMA=n because I figured that my
>> patchset might not handle NUMA properly). Mem region size = 512 MB.
>>
> 
> For CONFIG_NUMA=y on the same machine, the difference between the 2 kernels
> was much lesser, but nevertheless, this patchset performed better. I wouldn't
> vouch that my patchset handles NUMA correctly, but here are the numbers from
> that run anyway (at least to show that I really found the results to be
> repeatable):
> 
> Kernbench log for Vanilla 3.7-rc3
> =================================
> Kernel: 3.7.0-rc3-vanilla-numa-default
> Average Optimal load -j 32 Run (std deviation):
> Elapsed Time 589.058 (0.596171)
> User Time 7461.26 (1.69702)
> System Time 1072.03 (1.54704)
> Percent CPU 1448.2 (1.30384)
> Context Switches 2.14322e+06 (4042.97)
> Sleeps 1847230 (2614.96)
> 
> Kernbench log for Vanilla 3.7-rc3
> =================================

Oops, that title must have been "for sorted-buddy patchset" of course..

> Kernel: 3.7.0-rc3-sorted-buddy-numa-default
> Average Optimal load -j 32 Run (std deviation):
> Elapsed Time 577.182 (0.713772)
> User Time 7315.43 (3.87226)
> System Time 1043 (1.12855)
> Percent CPU 1447.6 (2.19089)
> Context Switches 2117022 (3810.15)
> Sleeps 1.82966e+06 (4149.82)
> 
> 

Regards,
Srivatsa S. Bhat

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