On Thu, Oct 04, 2007 at 10:38:15AM -0700, Christoph Lameter wrote: > On Thu, 4 Oct 2007, Matthew Wilcox wrote: > > > So, on "a well-known OLTP benchmark which prohibits publishing absolute > > numbers" and on an x86-64 system (I don't think exactly which model > > is important), we're seeing *6.51%* performance loss on slub vs slab. > > This is with a 2.6.23-rc3 kernel. Tuning the boot parameters, as you've > > asked for before (slub_min_order=2, slub_max_order=4, slub_min_objects=8) > > gets back 0.38% of that. It's still down 6.13% over slab. > > Yeah the fastpath vs. slow path is not the issue as Siddha and I concluded > earlier. Seems that we are mainly seeing cacheline bouncing due to two > cpus accessing meta data in the same page struct. The patches in > MM that are scheduled to be merged for .24 address that issue. I > have repeatedly asked that these patches be tested. The patches were > posted months ago.
I just checked with the guys who did the test. When I said -rc3, I mis-spoke; this is 2.6.23-rc3 *plus* the patches which Suresh agreed to test for you. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
