Re: [rfc][patch] SLQB slab allocator

MinChan Kim
2008-12-17T06:59:23Z

On Wed, Dec 17, 2008 at 3:42 PM, Nick Piggin <npiggin@suse.de> wrote:
> On Tue, Dec 16, 2008 at 08:42:12AM +0900, MinChan Kim wrote:
>> Hi, Nick.
>> I am interested in SLQB.
>> So I tested slqb, slub, slab by kernel compile time.
>>
>> make all -j 8
>>
>> slqb and slub not DEBUG.
>> my test environment is as follows.
>>
>> cpu family : 6
>> model : 15
>> model name : Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz
>> stepping : 11
>> cpu MHz : 1600.000
>> cache size : 4096 KB
>>
>> Below is average for ten time test.
>>
>> slab :
>> user : 2376.484, system : 192.616 elapsed : 12:22.0
>> slub :
>> user : 2378.439, system : 194.989 elapsed : 12:22.4
>> slqb :
>> user : 2380.556, system : 194.801 elapsed : 12:23.0
>>
>> so, slqb is rather slow although it is a big difference.
>> Interestingly, slqb consumes less time than slub in system.
>
> Thanks, interesting test. kbuild is not very slab allocator intensive,

Let me know what is popular benchmark program in slab allocator.
I will try with it. :)

> so I hadn't thought of trying it. Possibly the object cacheline layout
> of longer lived allocations changes the behaviour (increased user time
> could indicate that).

What mean "object cacheline layout of loger lived allocations" ?

> I've been making a few changes to that, and hopefully slqb is slightly
> improved now (the margin is much closer, seems within the noise with
> SLUB on my NUMA opteron now, although that's a very different system).
>
> The biggest bug I fixed was that the NUMA path wasn't being taken in
> kmem_cache_free on NUMA systems (oops), but that wouldn't change your
> result. But I did make some other changes too, eg in prefetching.

OK. I will review and test your new patch in my machine.

--
Kinds regards,
MinChan Kim
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