From: Peter Zijlstra <peterz@infradead.org> To: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Mel Gorman <mgorman@suse.de>, Ingo Molnar <mingo@kernel.org>, Andrea Arcangeli <aarcange@redhat.com>, Johannes Weiner <hannes@cmpxchg.org>, Linux-MM <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org> Subject: Re: [PATCH 5/8] sched: Favour moving tasks towards the preferred node Date: Fri, 28 Jun 2013 11:04:47 +0200 [thread overview] Message-ID: <20130628090447.GD28407@twins.programming.kicks-ass.net> (raw) In-Reply-To: <20130628081120.GE17195@linux.vnet.ibm.com> On Fri, Jun 28, 2013 at 01:41:20PM +0530, Srikar Dronamraju wrote: Please trim your replies. > > +/* Returns true if the destination node has incurred more faults */ > > +static bool migrate_improves_locality(struct task_struct *p, struct lb_env *env) > > +{ > > + int src_nid, dst_nid; > > + > > + if (!p->numa_faults || !(env->sd->flags & SD_NUMA)) > > + return false; > > + > > + src_nid = cpu_to_node(env->src_cpu); > > + dst_nid = cpu_to_node(env->dst_cpu); > > + > > + if (src_nid == dst_nid) > > + return false; > > + > > + if (p->numa_migrate_seq < sysctl_numa_balancing_settle_count && > > Lets say even if the numa_migrate_seq is greater than settle_count but running > on a wrong node, then shouldnt this be taken as a good opportunity to > move the task? I think that's what its doing; so this stmt says; if seq is large and we're trying to move to the 'right' node; move it noaw. > > + p->numa_preferred_nid == dst_nid) > > + return true; > > + > > + return false; > > +} > > + > > + > > /* > > * can_migrate_task - may task p from runqueue rq be migrated to this_cpu? > > */ > > @@ -3945,10 +3977,14 @@ int can_migrate_task(struct task_struct *p, struct lb_env *env) > > > > /* > > * Aggressive migration if: > > - * 1) task is cache cold, or > > - * 2) too many balance attempts have failed. > > + * 1) destination numa is preferred > > + * 2) task is cache cold, or > > + * 3) too many balance attempts have failed. > > */ > > > > + if (migrate_improves_locality(p, env)) > > + return 1; > > Shouldnt this be under tsk_cache_hot check? > > If the task is cache hot, then we would have to update the corresponding schedstat > metrics. No; you want migrate_degrades_locality() to be like task_hot(). You want to _always_ migrate tasks towards better locality irrespective of local cache hotness.
WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org> To: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Mel Gorman <mgorman@suse.de>, Ingo Molnar <mingo@kernel.org>, Andrea Arcangeli <aarcange@redhat.com>, Johannes Weiner <hannes@cmpxchg.org>, Linux-MM <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org> Subject: Re: [PATCH 5/8] sched: Favour moving tasks towards the preferred node Date: Fri, 28 Jun 2013 11:04:47 +0200 [thread overview] Message-ID: <20130628090447.GD28407@twins.programming.kicks-ass.net> (raw) In-Reply-To: <20130628081120.GE17195@linux.vnet.ibm.com> On Fri, Jun 28, 2013 at 01:41:20PM +0530, Srikar Dronamraju wrote: Please trim your replies. > > +/* Returns true if the destination node has incurred more faults */ > > +static bool migrate_improves_locality(struct task_struct *p, struct lb_env *env) > > +{ > > + int src_nid, dst_nid; > > + > > + if (!p->numa_faults || !(env->sd->flags & SD_NUMA)) > > + return false; > > + > > + src_nid = cpu_to_node(env->src_cpu); > > + dst_nid = cpu_to_node(env->dst_cpu); > > + > > + if (src_nid == dst_nid) > > + return false; > > + > > + if (p->numa_migrate_seq < sysctl_numa_balancing_settle_count && > > Lets say even if the numa_migrate_seq is greater than settle_count but running > on a wrong node, then shouldnt this be taken as a good opportunity to > move the task? I think that's what its doing; so this stmt says; if seq is large and we're trying to move to the 'right' node; move it noaw. > > + p->numa_preferred_nid == dst_nid) > > + return true; > > + > > + return false; > > +} > > + > > + > > /* > > * can_migrate_task - may task p from runqueue rq be migrated to this_cpu? > > */ > > @@ -3945,10 +3977,14 @@ int can_migrate_task(struct task_struct *p, struct lb_env *env) > > > > /* > > * Aggressive migration if: > > - * 1) task is cache cold, or > > - * 2) too many balance attempts have failed. > > + * 1) destination numa is preferred > > + * 2) task is cache cold, or > > + * 3) too many balance attempts have failed. > > */ > > > > + if (migrate_improves_locality(p, env)) > > + return 1; > > Shouldnt this be under tsk_cache_hot check? > > If the task is cache hot, then we would have to update the corresponding schedstat > metrics. No; you want migrate_degrades_locality() to be like task_hot(). You want to _always_ migrate tasks towards better locality irrespective of local cache hotness. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2013-06-28 9:04 UTC|newest] Thread overview: 124+ messages / expand[flat|nested] mbox.gz Atom feed top 2013-06-26 14:37 [PATCH 0/6] Basic scheduler support for automatic NUMA balancing Mel Gorman 2013-06-26 14:37 ` Mel Gorman 2013-06-26 14:38 ` [PATCH 1/8] mm: numa: Document automatic NUMA balancing sysctls Mel Gorman 2013-06-26 14:38 ` Mel Gorman 2013-06-26 14:38 ` [PATCH 2/8] sched: Track NUMA hinting faults on per-node basis Mel Gorman 2013-06-26 14:38 ` Mel Gorman 2013-06-27 15:57 ` Peter Zijlstra 2013-06-27 15:57 ` Peter Zijlstra 2013-06-28 12:22 ` Mel Gorman 2013-06-28 12:22 ` Mel Gorman 2013-06-28 6:08 ` Srikar Dronamraju 2013-06-28 6:08 ` Srikar Dronamraju 2013-06-28 8:56 ` Peter Zijlstra 2013-06-28 8:56 ` Peter Zijlstra 2013-06-28 12:30 ` Mel Gorman 2013-06-28 12:30 ` Mel Gorman 2013-06-26 14:38 ` [PATCH 3/8] sched: Select a preferred node with the most numa hinting faults Mel Gorman 2013-06-26 14:38 ` Mel Gorman 2013-06-28 6:14 ` Srikar Dronamraju 2013-06-28 6:14 ` Srikar Dronamraju 2013-06-28 8:59 ` Peter Zijlstra 2013-06-28 8:59 ` Peter Zijlstra 2013-06-28 10:24 ` Srikar Dronamraju 2013-06-28 10:24 ` Srikar Dronamraju 2013-06-28 12:33 ` Mel Gorman 2013-06-28 12:33 ` Mel Gorman 2013-06-26 14:38 ` [PATCH 4/8] sched: Update NUMA hinting faults once per scan Mel Gorman 2013-06-26 14:38 ` Mel Gorman 2013-06-28 6:32 ` Srikar Dronamraju 2013-06-28 6:32 ` Srikar Dronamraju 2013-06-28 9:01 ` Peter Zijlstra 2013-06-28 9:01 ` Peter Zijlstra 2013-06-26 14:38 ` [PATCH 5/8] sched: Favour moving tasks towards the preferred node Mel Gorman 2013-06-26 14:38 ` Mel Gorman 2013-06-27 14:52 ` Peter Zijlstra 2013-06-27 14:52 ` Peter Zijlstra 2013-06-27 14:53 ` Peter Zijlstra 2013-06-27 14:53 ` Peter Zijlstra 2013-06-28 13:00 ` Mel Gorman 2013-06-28 13:00 ` Mel Gorman 2013-06-27 16:01 ` Peter Zijlstra 2013-06-27 16:01 ` Peter Zijlstra 2013-06-28 13:01 ` Mel Gorman 2013-06-28 13:01 ` Mel Gorman 2013-06-27 16:11 ` Peter Zijlstra 2013-06-27 16:11 ` Peter Zijlstra 2013-06-28 13:45 ` Mel Gorman 2013-06-28 13:45 ` Mel Gorman 2013-06-28 15:10 ` Peter Zijlstra 2013-06-28 15:10 ` Peter Zijlstra 2013-06-28 8:11 ` Srikar Dronamraju 2013-06-28 8:11 ` Srikar Dronamraju 2013-06-28 9:04 ` Peter Zijlstra [this message] 2013-06-28 9:04 ` Peter Zijlstra 2013-06-28 10:07 ` Srikar Dronamraju 2013-06-28 10:07 ` Srikar Dronamraju 2013-06-28 10:24 ` Peter Zijlstra 2013-06-28 10:24 ` Peter Zijlstra 2013-06-28 13:51 ` Mel Gorman 2013-06-28 13:51 ` Mel Gorman 2013-06-28 17:14 ` Srikar Dronamraju 2013-06-28 17:14 ` Srikar Dronamraju 2013-06-28 17:34 ` Mel Gorman 2013-06-28 17:34 ` Mel Gorman 2013-06-28 17:44 ` Srikar Dronamraju 2013-06-28 17:44 ` Srikar Dronamraju 2013-06-26 14:38 ` [PATCH 6/8] sched: Reschedule task on preferred NUMA node once selected Mel Gorman 2013-06-26 14:38 ` Mel Gorman 2013-06-27 14:54 ` Peter Zijlstra 2013-06-27 14:54 ` Peter Zijlstra 2013-06-28 13:54 ` Mel Gorman 2013-06-28 13:54 ` Mel Gorman 2013-07-02 12:06 ` Srikar Dronamraju 2013-07-02 12:06 ` Srikar Dronamraju 2013-07-02 16:29 ` Mel Gorman 2013-07-02 16:29 ` Mel Gorman 2013-07-02 18:17 ` Peter Zijlstra 2013-07-02 18:17 ` Peter Zijlstra 2013-07-06 6:44 ` Srikar Dronamraju 2013-07-06 6:44 ` Srikar Dronamraju 2013-07-06 10:47 ` Peter Zijlstra 2013-07-06 10:47 ` Peter Zijlstra 2013-07-02 18:15 ` Peter Zijlstra 2013-07-02 18:15 ` Peter Zijlstra 2013-07-03 9:50 ` Peter Zijlstra 2013-07-03 9:50 ` Peter Zijlstra 2013-07-03 15:28 ` Mel Gorman 2013-07-03 15:28 ` Mel Gorman 2013-07-03 18:46 ` Peter Zijlstra 2013-07-03 18:46 ` Peter Zijlstra 2013-06-26 14:38 ` [PATCH 7/8] sched: Split accounting of NUMA hinting faults that pass two-stage filter Mel Gorman 2013-06-26 14:38 ` Mel Gorman 2013-06-27 14:56 ` Peter Zijlstra 2013-06-27 14:56 ` Peter Zijlstra 2013-06-28 14:00 ` Mel Gorman 2013-06-28 14:00 ` Mel Gorman 2013-06-28 7:00 ` Srikar Dronamraju 2013-06-28 7:00 ` Srikar Dronamraju 2013-06-28 9:36 ` Peter Zijlstra 2013-06-28 9:36 ` Peter Zijlstra 2013-06-28 10:12 ` Srikar Dronamraju 2013-06-28 10:12 ` Srikar Dronamraju 2013-06-28 10:33 ` Peter Zijlstra 2013-06-28 10:33 ` Peter Zijlstra 2013-06-28 14:29 ` Mel Gorman 2013-06-28 14:29 ` Mel Gorman 2013-06-28 15:12 ` Peter Zijlstra 2013-06-28 15:12 ` Peter Zijlstra 2013-06-26 14:38 ` [PATCH 8/8] sched: Increase NUMA PTE scanning when a new preferred node is selected Mel Gorman 2013-06-26 14:38 ` Mel Gorman 2013-06-27 14:59 ` [PATCH 0/6] Basic scheduler support for automatic NUMA balancing Peter Zijlstra 2013-06-27 14:59 ` Peter Zijlstra 2013-06-28 13:54 ` Srikar Dronamraju 2013-06-28 13:54 ` Srikar Dronamraju 2013-07-01 5:39 ` Srikar Dronamraju 2013-07-01 5:39 ` Srikar Dronamraju 2013-07-01 8:43 ` Mel Gorman 2013-07-01 8:43 ` Mel Gorman 2013-07-02 5:28 ` Srikar Dronamraju 2013-07-02 5:28 ` Srikar Dronamraju 2013-07-02 7:46 ` Peter Zijlstra 2013-07-02 7:46 ` Peter Zijlstra 2013-07-02 8:55 ` Peter Zijlstra 2013-07-02 8:55 ` Peter Zijlstra
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