On Fri, Jun 14, 2013 at 10:35:22PM -0700, Tejun Heo wrote: > On Fri, Jun 14, 2013 at 03:31:25PM -0700, Tejun Heo wrote: > > I'll play with it a bit more on an actual machine and post more > > results. Test program attached. > > So, here are the results from the same test on a dual-socket 2-way > NUMA opteron 8 core machine. > > Running on one CPU. > > copy size atomic percpu diff in pct > 0 535964443 616756827 +15.07% > 32 399988186 378678713 -5.33% > 64 389067476 355073979 -8.74% > 128 342192631 315615300 -7.77% > 256 281208005 260598931 -7.33% > 512 188070912 193225269 +2.74% > > Running on all eight cores. > > copy size atomic percpu diff in pct > 0 121324328 4889425511 +3,930.05% > 32 96170193 2999613380 +3,019.07% > 64 98139061 2813894184 +2,767.25% > 128 112610025 2503229487 +2,122.92% > 256 96828114 2069865752 +2,037.67% > 512 95858297 1537726109 +1,504.17%
A bit of addition, this of course is completely synthetic and exaggerates the differences both ways, but it's pretty clear that this is gonna be a clear gain in any kind of workload which would generate some amount of cross-CPU refcnting, which would be the norm anyway. Thanks. -- tejun -- 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/
