On Wed, Nov 21, 2012 at 07:21:58PM +0100, Ingo Molnar wrote: > > * Mel Gorman <mgorman@xxxxxxx> wrote: > > > On Wed, Nov 21, 2012 at 06:33:16PM +0100, Ingo Molnar wrote: > > > > > > * Mel Gorman <mgorman@xxxxxxx> wrote: > > > > > > > On Wed, Nov 21, 2012 at 06:03:06PM +0100, Ingo Molnar wrote: > > > > > > > > > > * Mel Gorman <mgorman@xxxxxxx> wrote: > > > > > > > > > > > On Wed, Nov 21, 2012 at 10:21:06AM +0000, Mel Gorman wrote: > > > > > > > > > > > > > > I am not including a benchmark report in this but will be posting one > > > > > > > shortly in the "Latest numa/core release, v16" thread along with the latest > > > > > > > schednuma figures I have available. > > > > > > > > > > > > > > > > > > > Report is linked here https://lkml.org/lkml/2012/11/21/202 > > > > > > > > > > > > I ended up cancelling the remaining tests and restarted with > > > > > > > > > > > > 1. schednuma + patches posted since so that works out as > > > > > > > > > > Mel, I'd like to ask you to refer to our tree as numa/core or > > > > > 'numacore' in the future. Would such a courtesy to use the > > > > > current name of our tree be possible? > > > > > > > > > > > > > Sure, no problem. > > > > > > Thanks! > > > > > > I ran a quick test with your 'balancenuma v4' tree and while > > > numa02 and numa01-THREAD-ALLOC performance is looking good, > > > numa01 performance does not look very good: > > > > > > mainline numa/core balancenuma-v4 > > > numa01: 340.3 139.4 276 secs > > > > > > 97% slower than numa/core. > > > > > > > It would be. numa01 is an adverse workload where all threads > > are hammering the same memory. The two-stage filter in > > balancenuma restricts the amount of migration it does so it > > ends up in a situation where it cannot balance properly. [...] > > Do you mean this "balancenuma v4" patch attributed to you: > > Subject: mm: Numa: Use a two-stage filter to restrict pages being migrated for unlikely task<->node relationships > From: Mel Gorman <mgorman@xxxxxxx> > Date: Wed, 21 Nov 2012 10:21:42 +0000 > Yes. > ... > > Signed-off-by: Mel Gorman <mgorman@xxxxxxx> > > which has: > > /* > * Multi-stage node selection is used in conjunction > * with a periodic migration fault to build a temporal > * task<->page relation. By using a two-stage filter we > * remove short/unlikely relations. > * > * Using P(p) ~ n_p / n_t as per frequentist > * probability, we can equate a task's usage of a > * particular page (n_p) per total usage of this > * page (n_t) (in a given time-span) to a probability. > * > * Our periodic faults will sample this probability and > * getting the same result twice in a row, given these > * samples are fully independent, is then given by > * P(n)^2, provided our sample period is sufficiently > * short compared to the usage pattern. > * > * This quadric squishes small probabilities, making > * it less likely we act on an unlikely task<->page > * relation. > > This looks very similar to the code and text that Peter wrote > for numa/core: > > /* > * Multi-stage node selection is used in conjunction with a periodic > * migration fault to build a temporal task<->page relation. By > * using a two-stage filter we remove short/unlikely relations. > * > * Using P(p) ~ n_p / n_t as per frequentist probability, we can > * equate a task's usage of a particular page (n_p) per total usage > * of this page (n_t) (in a given time-span) to a probability. > * > * Our periodic faults will then sample this probability and getting > * the same result twice in a row, given these samples are fully > * independent, is then given by P(n)^2, provided our sample period > * is sufficiently short compared to the usage pattern. > * > * This quadric squishes small probabilities, making it less likely > * we act on an unlikely task<->page relation. > * > * Return the best node ID this page should be on, or -1 if it should > * stay where it is. > */ > > see commit: > > 30f93abc6cb3 sched, numa, mm: Add the scanning page fault machinery > > ? > > I think it's the very same concept - yours is taken from an > older sched/numa commit and attributed to yourself? [If so then > please fix the attribution.] Yes, it's completely based on earlier sched/numa patches. In many of the patches you'll see notes where I documented what patches I originally based on -- be it from sched/numa, autonuma or some combination of both. In many cases I could not keep the signed-off-by because the end result was simply too different to claim that the author was happy with it. I was hoping that these notes would convert to signed-offs-by after review from the original authors who were cc'd at all times. > We have the same filter in numa/core - because we wrote it (FYI, > I wrote bits of the last_cpu variant in numa/core), yet our > numa01 performance is much better than the one of balancenuma. > Yes, the lack of a note was a mistake. I've added the following note to the top of this patch now Note: This two-stage filter was taken directly from the sched/numa patch "sched, numa, mm: Add the scanning page fault machinery" but is only a partial extraction. As the end result is not necessarily recognisable, the signed-offs-by had to be removed. Will be added back if requested. Thanks and apologies in advance for any other patch where I failed to document the history correctly. -- Mel Gorman SUSE Labs -- 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>