From: Mel Gorman <mgorman@suse.de>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Alex Thorlton <athorlton@sgi.com>, Rik van Riel <riel@redhat.com>,
Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 17/18] sched: Add tracepoints related to NUMA task migration
Date: Wed, 11 Dec 2013 08:37:45 +0000 [thread overview]
Message-ID: <20131211083744.GP11295@suse.de> (raw)
In-Reply-To: <20131210142211.099fe782c361707ab3c04742@linux-foundation.org>
On Tue, Dec 10, 2013 at 02:22:11PM -0800, Andrew Morton wrote:
> On Tue, 10 Dec 2013 15:51:35 +0000 Mel Gorman <mgorman@suse.de> wrote:
>
> > This patch adds three tracepoints
> > o trace_sched_move_numa when a task is moved to a node
> > o trace_sched_swap_numa when a task is swapped with another task
> > o trace_sched_stick_numa when a numa-related migration fails
> >
> > The tracepoints allow the NUMA scheduler activity to be monitored and the
> > following high-level metrics can be calculated
> >
> > o NUMA migrated stuck nr trace_sched_stick_numa
> > o NUMA migrated idle nr trace_sched_move_numa
> > o NUMA migrated swapped nr trace_sched_swap_numa
> > o NUMA local swapped trace_sched_swap_numa src_nid == dst_nid (should never happen)
> > o NUMA remote swapped trace_sched_swap_numa src_nid != dst_nid (should == NUMA migrated swapped)
> > o NUMA group swapped trace_sched_swap_numa src_ngid == dst_ngid
> > Maybe a small number of these are acceptable
> > but a high number would be a major surprise.
> > It would be even worse if bounces are frequent.
> > o NUMA avg task migs. Average number of migrations for tasks
> > o NUMA stddev task mig Self-explanatory
> > o NUMA max task migs. Maximum number of migrations for a single task
> >
> > In general the intent of the tracepoints is to help diagnose problems
> > where automatic NUMA balancing appears to be doing an excessive amount of
> > useless work.
> >
> > ...
> >
> > --- a/kernel/sched/fair.c
> > +++ b/kernel/sched/fair.c
> > @@ -1272,11 +1272,13 @@ static int task_numa_migrate(struct task_struct *p)
> > p->numa_scan_period = task_scan_min(p);
> >
> > if (env.best_task == NULL) {
> > - int ret = migrate_task_to(p, env.best_cpu);
> > + if ((ret = migrate_task_to(p, env.best_cpu)) != 0)
> > + trace_sched_stick_numa(p, env.src_cpu, env.best_cpu);
> > return ret;
> > }
> >
> > - ret = migrate_swap(p, env.best_task);
> > + if ((ret = migrate_swap(p, env.best_task)) != 0);
>
> I'll zap that semicolon...
>
Thanks
--
Mel Gorman
SUSE Labs
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next prev parent reply other threads:[~2013-12-11 8:37 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-10 15:51 [PATCH 00/17] NUMA balancing segmentation fault fixes and misc followups v4 Mel Gorman
2013-12-10 15:51 ` [PATCH 01/18] mm: numa: Serialise parallel get_user_page against THP migration Mel Gorman
2013-12-10 15:51 ` [PATCH 02/18] mm: numa: Call MMU notifiers on " Mel Gorman
2013-12-10 15:51 ` [PATCH 03/18] mm: Clear pmd_numa before invalidating Mel Gorman
2013-12-10 15:51 ` [PATCH 04/18] mm: numa: Do not clear PMD during PTE update scan Mel Gorman
2013-12-10 15:51 ` [PATCH 05/18] mm: numa: Do not clear PTE for pte_numa update Mel Gorman
2013-12-16 23:15 ` [PATCH 19/18] mm,numa: write pte_numa pte back to the page tables Rik van Riel
2013-12-10 15:51 ` [PATCH 06/18] mm: numa: Ensure anon_vma is locked to prevent parallel THP splits Mel Gorman
2013-12-10 15:51 ` [PATCH 07/18] mm: numa: Avoid unnecessary work on the failure path Mel Gorman
2013-12-10 15:51 ` [PATCH 08/18] sched: numa: Skip inaccessible VMAs Mel Gorman
2013-12-10 15:51 ` [PATCH 09/18] mm: numa: Clear numa hinting information on mprotect Mel Gorman
2013-12-10 15:51 ` [PATCH 10/18] mm: numa: Avoid unnecessary disruption of NUMA hinting during migration Mel Gorman
2013-12-17 22:53 ` Sasha Levin
2013-12-19 11:59 ` Mel Gorman
2013-12-19 12:00 ` [PATCH] mm: Remove bogus warning in copy_huge_pmd Mel Gorman
2013-12-19 18:36 ` Rik van Riel
2013-12-10 15:51 ` [PATCH 11/18] mm: fix TLB flush race between migration, and change_protection_range Mel Gorman
2013-12-11 19:12 ` [PATCH] mm: fix TLB flush race between migration, and change_protection_range -fix Mel Gorman
2013-12-10 15:51 ` [PATCH 12/18] mm: numa: Defer TLB flush for THP migration as long as possible Mel Gorman
2013-12-10 16:56 ` Rik van Riel
2013-12-10 15:51 ` [PATCH 13/18] mm: numa: Make NUMA-migrate related functions static Mel Gorman
2013-12-10 15:51 ` [PATCH 14/18] mm: numa: Limit scope of lock for NUMA migrate rate limiting Mel Gorman
2013-12-10 15:51 ` [PATCH 15/18] mm: numa: Trace tasks that fail migration due to " Mel Gorman
2013-12-10 15:51 ` [PATCH 16/18] mm: numa: Do not automatically migrate KSM pages Mel Gorman
2013-12-10 15:51 ` [PATCH 17/18] sched: Add tracepoints related to NUMA task migration Mel Gorman
2013-12-10 22:22 ` Andrew Morton
2013-12-11 8:37 ` Mel Gorman [this message]
2013-12-10 15:56 ` [PATCH 00/17] NUMA balancing segmentation fault fixes and misc followups v4 Mel Gorman
2013-12-11 13:21 ` [PATCH] mm: numa: Guarantee that tlb_flush_pending updates are visible before page table updates Mel Gorman
2013-12-11 14:44 ` Paul E. McKenney
2013-12-11 16:40 ` Mel Gorman
2013-12-11 16:56 ` Paul E. McKenney
2013-12-11 15:21 ` Rik van Riel
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