On Fri, 29 Jun 2012, Andrew Morton wrote: > > I've tested this patch on numa machines with 2, 4 and 8 nodes and > > measured speed of memory access inside of KVM guests with memory pinned > > to one of nodes with this benchmark: > > > > http://pholasek.fedorapeople.org/alloc_pg.c > > > > Population standard deviations of access times in percentage of average > > were following: > > > > merge_nodes=1 > > 2 nodes 1.4% > > 4 nodes 1.6% > > 8 nodes 1.7% > > > > merge_nodes=0 > > 2 nodes 1% > > 4 nodes 0.32% > > 8 nodes 0.018% > > ooh, numbers! Thanks. > Ok, the standard deviation increases when merging pages from nodes with remote distance, that makes sense. But if that's true, then you would restrict either the entire application to local memory with mempolicies or cpusets, or you would use mbind() to restrict this memory to that set of nodes already so that accesses, even with ksm merging, would have affinity. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>