Re: [PATCH 1/3 v2] slub: prefetch next freelist pointer in __slab_alloc()

[JoonSoo Kim <js1304@gmail.com>]

2012/7/5 Pekka Enberg <penberg@kernel.org>:
> On Wed, Jul 4, 2012 at 6:45 PM, JoonSoo Kim <js1304@gmail.com> wrote:
>>> Prefetching can also have negative effect on overall performance:
>>>
>>> http://lwn.net/Articles/444336/
>>
>> Thanks for good article which is very helpful to me.
>>
>>> That doesn't seem like that obvious win to me... Eric, Christoph?
>>
>> Could you tell me how I test this patch more deeply, plz?
>> I am a kernel newbie and in the process of learning.
>> I doesn't know what I can do more for this.
>> I googling previous patch related to slub, some people use netperf.
>>
>> Just do below is sufficient?
>> How is this test related to slub?
>>
>> for in in `seq 1 32`
>> do
>>  netperf -H 192.168.0.8 -v 0 -l -100000 -t TCP_RR > /dev/null &
>> done
>> wait
>
> The networking subsystem is sensitive to slab allocator performance
> which makes netperf an interesting benchmark, that's all.
>
> As for slab benchmarking, you might want to look at what Mel Gorman
> has done in the past:
>
> https://lkml.org/lkml/2009/2/16/252
>
> For something like prefetch optimization, you'd really want to see a
> noticeable win in some benchmark. The kind of improvement you're
> seeing with your patch is likely to be lost in the noise - or even
> worse, cause negative performance for real world workloads.

Okay.
Thanks for comments.

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