Re: Mainline kernel OLTP performance update

Pekka Enberg
2009-01-16T10:55:34Z

Hi Nick,

On Fri, Jan 16, 2009 at 12:42 PM, Nick Piggin <nickpiggin@yahoo.com.au> wrote:
>> I don't have the exact config for the previous tests but it's was just
>> my laptop regular config whereas the new tests are x86-64 defconfig.
>> So I think I'm just hitting some of the other OLTP regressions here,
>> aren't I? There's some scheduler related options such as
>> CONFIG_GROUP_SCHED and CONFIG_FAIR_GROUP_SCHED enabled in defconfig
>> that I didn't have in the original tests. I can try without them if
>> you want but I'm not sure it's relevant for SLAB vs SLUB tests.
>
> Oh no that's fine. It just looked like you repeated the test but
> with lockdep disabled (and no other changes).

Right. In any case, I am still unable to reproduce the OLTP issue and
I've seen SLUB beat SLAB on my machine in most of the benchmarks
you've posted. So I have very mixed feelings about SLQB. It's very
nice that it works for OLTP but we still don't have much insight (i.e.
numbers) on why it's better. I'm also bit worried if SLQB has gotten
enough attention from the NUMA and HPC folks that brought us SLUB.

The good news is that SLQB can replace SLAB so either way, we're not
going to end up with four allocators. Whether it can replace SLUB
remains to be seen.

Pekka