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. After I change kmalloc-8192/order to 3, the result(pinned netperf UDP-U-4k) difference between SLUB and SLQB becomes 1% which can be considered as fluctuation. But when trying to increased it to 4, I got: [root@lkp-st02-x8664 slab]# echo "3">kmalloc-8192/order [root@lkp-st02-x8664 slab]# echo "4">kmalloc-8192/order -bash: echo: write error: Invalid argument Comparing with SLQB, it seems SLUB needs too many investigation/manual finer-tuning against specific benchmarks. One hard is to tune page order number. Although SLQB also has many tuning options, I almost doesn't tune it manually, just run benchmark and collect results to compare. Does that mean the scalability of SLQB is better? -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
