Messages in this thread | | | Subject | Re: Mainline kernel OLTP performance update | From | Pekka Enberg <> | Date | Fri, 23 Jan 2009 17:31:31 +0200 |
| |
On Fri, 2009-01-23 at 10:22 -0500, Christoph Lameter wrote: > On Fri, 23 Jan 2009, Pekka Enberg wrote: > > > Looking at __slab_free(), unless page->inuse is constantly zero and we > > discard the slab, it really is just cache effects (10% sounds like a > > lot, though!). AFAICT, the only way to optimize that is with Christoph's > > unfinished pointer freelists patches or with a remote free list like in > > SLQB. > > No there is another way. Increase the allocator order to 3 for the > kmalloc-8192 slab then multiple 8k blocks can be allocated from one of the > larger chunks of data gotten from the page allocator. That will allow slub > to do fast allocs.
I wonder why that doesn't happen already, actually. The slub_max_order know is capped to PAGE_ALLOC_COSTLY_ORDER ("3") by default and obviously order 3 should be as good fit as order 2 so 'fraction' can't be too high either. Hmm.
Pekka
| |