On Wed, Jul 30, 2014 at 10:25:03AM -0400, Rik van Riel wrote: > On 07/29/2014 10:14 PM, Aaron Lu wrote: > > On Tue, Jul 29, 2014 at 04:04:37PM -0400, Rik van Riel wrote: > >> On Tue, 29 Jul 2014 10:17:12 +0200 > >> Peter Zijlstra <pet...@infradead.org> wrote: > >> > >>>> +#define NUMA_SCALE 1000 > >>>> +#define NUMA_MOVE_THRESH 50 > >>> > >>> Please make that 1024, there's no reason not to use power of two here. > >>> This base 10 factor thing annoyed me no end already, its time for it to > >>> die. > >> > >> That's easy enough. However, it would be good to know whether > >> this actually helps with the regression Aaron found :) > > > > Sorry for the delay. > > > > I applied the last patch and queued the hackbench job to the ivb42 test > > machine for it to run 5 times, and here is the result(regarding the > > proc-vmstat.numa_hint_faults_local field): > > 173565 > > 201262 > > 192317 > > 198342 > > 198595 > > avg: > > 192816 > > > > It seems it is still very big than previous kernels. > > It looks like a step in the right direction, though. > > Could you try running with a larger threshold? > > >> +++ b/kernel/sched/fair.c > >> @@ -924,10 +924,12 @@ static inline unsigned long group_faults_cpu(struct > >> numa_group *group, int nid) > >> > >> /* > >> * These return the fraction of accesses done by a particular task, or > >> - * task group, on a particular numa node. The group weight is given a > >> - * larger multiplier, in order to group tasks together that are almost > >> - * evenly spread out between numa nodes. > >> + * task group, on a particular numa node. The NUMA move threshold > >> + * prevents task moves with marginal improvement, and is set to 5%. > >> */ > >> +#define NUMA_SCALE 1024 > >> +#define NUMA_MOVE_THRESH (5 * NUMA_SCALE / 100) > > It would be good to see if changing NUMA_MOVE_THRESH to > (NUMA_SCALE / 8) does the trick.
With your 2nd patch and the above change, the result is: "proc-vmstat.numa_hint_faults_local": [ 199708, 209152, 200638, 187324, 196654 ], avg: 198695 Regards, Aaron -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
