Messages in this thread | | | Date | Thu, 27 Sep 2012 11:45:14 -0400 | From | Rik van Riel <> | Subject | Re: [PATCH v4] KSM: numa awareness sysfs knob |
| |
On 09/23/2012 08:56 PM, Petr Holasek wrote: > Introduces new sysfs boolean knob /sys/kernel/mm/ksm/merge_across_nodes > which control merging pages across different numa nodes. > When it is set to zero only pages from the same node are merged, > otherwise pages from all nodes can be merged together (default behavior). > > Typical use-case could be a lot of KVM guests on NUMA machine > and cpus from more distant nodes would have significant increase > of access latency to the merged ksm page. Sysfs knob was choosen > for higher variability when some users still prefers higher amount > of saved physical memory regardless of access latency. > > Every numa node has its own stable & unstable trees because of faster > searching and inserting. Changing of merge_nodes value is possible only > when there are not any ksm shared pages in system. > > 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:
Acked-by: Rik van Riel <riel@redhat.com>
| |