| Date | Mon, 28 Jan 2013 15:03:04 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH 1/11] ksm: allow trees per NUMA node |
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On Fri, 25 Jan 2013 17:54:53 -0800 (PST) Hugh Dickins <hughd@google.com> wrote:
> --- mmotm.orig/Documentation/vm/ksm.txt 2013-01-25 14:36:31.724205455 -0800 > +++ mmotm/Documentation/vm/ksm.txt 2013-01-25 14:36:38.608205618 -0800 > @@ -58,6 +58,13 @@ sleep_millisecs - how many milliseconds > e.g. "echo 20 > /sys/kernel/mm/ksm/sleep_millisecs" > Default: 20 (chosen for demonstration purposes) > > +merge_across_nodes - specifies if pages from different numa nodes can be merged. > + When set to 0, ksm merges only pages which physically > + reside in the memory area of same NUMA node. It brings > + lower latency to access to shared page. Value can be > + changed only when there is no ksm shared pages in system. > + Default: 1 > +
The explanation doesn't really tell the operator whether or not to set merge_across_nodes for a particular machine/workload.
I guess most people will just shrug, turn the thing on and see if it improved things, but that's rather random.
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