Re: [PATCH] Autotune swappiness

From: Martin J. Bligh
Date: Fri Jul 09 2004 - 09:28:51 EST


>>> Here is another try at providing feedback to tune the vm_swappiness.
>>
>>
>> I spent some time yesterday trying to demonstrate performance improvements
>> from those two patches. Using
>>
>> make -j4 vmlinux with mem=64m
>>
>> and
>>
>> qsbench -p 4 -m 96 with mem=256m
>>
>> and was not able to do so, which is what I expected.
>>
>> We do need more quantitative testing on this work.
>
> Sure thing.
>
> I need to point out a few things:
> The point of this patch was to improve the swap behaviour on desktop like loads.
> The fact that it improved the "when swap is thrashing" scenario (in my testing) was an unintentional bonus.
> I dont think your load of j4 will induce quite the same swap thrash as what I was testing. I actually suspect the faster cpu & more jobs over fixed memory shows it more.
> I need someone with more varied hardware to test it for me. I can recreate equivalent results on my current machine which has similar hardware, but I think results showing improvement on different machines and different loads is what you're looking for... and since I'm currently quite low on hardware I can only offer results from this one (and my wife is hating it being offline o_0)
>
> Anyone willing to offer to do some tests?

What kind of mem pressure are you looking for? kernel compile is easy to run,
and straight "-j" should kill a small system fairly well ... you want it just
into swap, or thrashing the crap out of it?

M.

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