From: Peter Zijlstra <peterz@infradead.org>
To: Mel Gorman <mgorman@suse.de>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
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: [PATCH] sched, numa: Improve scanner
Date: Thu, 25 Jul 2013 12:41:30 +0200 [thread overview]
Message-ID: <20130725104130.GP27075@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <1373901620-2021-1-git-send-email-mgorman@suse.de>
Subject: sched, numa: Improve scanner
From: Peter Zijlstra <peterz@infradead.org>
Date: Tue Jul 23 17:02:38 CEST 2013
With a trace_printk("working\n"); right after the cmpxchg in
task_numa_work() we can see that of a 4 thread process, its always the
same task winning the race and doing the protection change.
This is a problem since the task doing the protection change has a
penalty for taking faults -- it is busy when marking the PTEs. If its
always the same task the ->numa_faults[] get severely skewed.
Avoid this by delaying the task doing the protection change such that
it is unlikely to win the privilege again.
Before:
root@interlagos:~# grep "thread 0/.*working" /debug/tracing/trace | tail -15
thread 0/0-3232 [022] .... 212.787402: task_numa_work: working
thread 0/0-3232 [022] .... 212.888473: task_numa_work: working
thread 0/0-3232 [022] .... 212.989538: task_numa_work: working
thread 0/0-3232 [022] .... 213.090602: task_numa_work: working
thread 0/0-3232 [022] .... 213.191667: task_numa_work: working
thread 0/0-3232 [022] .... 213.292734: task_numa_work: working
thread 0/0-3232 [022] .... 213.393804: task_numa_work: working
thread 0/0-3232 [022] .... 213.494869: task_numa_work: working
thread 0/0-3232 [022] .... 213.596937: task_numa_work: working
thread 0/0-3232 [022] .... 213.699000: task_numa_work: working
thread 0/0-3232 [022] .... 213.801067: task_numa_work: working
thread 0/0-3232 [022] .... 213.903155: task_numa_work: working
thread 0/0-3232 [022] .... 214.005201: task_numa_work: working
thread 0/0-3232 [022] .... 214.107266: task_numa_work: working
thread 0/0-3232 [022] .... 214.209342: task_numa_work: working
After:
root@interlagos:~# grep "thread 0/.*working" /debug/tracing/trace | tail -15
thread 0/0-3253 [005] .... 136.865051: task_numa_work: working
thread 0/2-3255 [026] .... 136.965134: task_numa_work: working
thread 0/3-3256 [024] .... 137.065217: task_numa_work: working
thread 0/3-3256 [024] .... 137.165302: task_numa_work: working
thread 0/3-3256 [024] .... 137.265382: task_numa_work: working
thread 0/0-3253 [004] .... 137.366465: task_numa_work: working
thread 0/2-3255 [026] .... 137.466549: task_numa_work: working
thread 0/0-3253 [004] .... 137.566629: task_numa_work: working
thread 0/0-3253 [004] .... 137.666711: task_numa_work: working
thread 0/1-3254 [028] .... 137.766799: task_numa_work: working
thread 0/0-3253 [004] .... 137.866876: task_numa_work: working
thread 0/2-3255 [026] .... 137.966960: task_numa_work: working
thread 0/1-3254 [028] .... 138.067041: task_numa_work: working
thread 0/2-3255 [026] .... 138.167123: task_numa_work: working
thread 0/3-3256 [024] .... 138.267207: task_numa_work: working
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
---
kernel/sched/fair.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1316,6 +1316,12 @@ void task_numa_work(struct callback_head
return;
/*
+ * Delay this task enough that another task of this mm will likely win
+ * the next time around.
+ */
+ p->node_stamp += 2 * TICK_NSEC;
+
+ /*
* Do not set pte_numa if the current running node is rate-limited.
* This loses statistics on the fault but if we are unwilling to
* migrate to this node, it is less likely we can do useful work
@@ -1405,7 +1411,7 @@ void task_tick_numa(struct rq *rq, struc
if (now - curr->node_stamp > period) {
if (!curr->node_stamp)
curr->numa_scan_period = task_scan_min(curr);
- curr->node_stamp = now;
+ curr->node_stamp += period;
if (!time_before(jiffies, curr->mm->numa_next_scan)) {
init_task_work(work, task_numa_work); /* TODO: move this into sched_fork() */
--
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next prev parent reply other threads:[~2013-07-25 10:41 UTC|newest]
Thread overview: 102+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-15 15:20 [PATCH 0/18] Basic scheduler support for automatic NUMA balancing V5 Mel Gorman
2013-07-15 15:20 ` [PATCH 01/18] mm: numa: Document automatic NUMA balancing sysctls Mel Gorman
2013-07-15 15:20 ` [PATCH 02/18] sched: Track NUMA hinting faults on per-node basis Mel Gorman
2013-07-17 10:50 ` Peter Zijlstra
2013-07-31 7:54 ` Mel Gorman
2013-07-29 10:10 ` Peter Zijlstra
2013-07-31 7:54 ` Mel Gorman
2013-07-15 15:20 ` [PATCH 03/18] mm: numa: Account for THP numa hinting faults on the correct node Mel Gorman
2013-07-17 0:33 ` Hillf Danton
2013-07-17 1:26 ` Wanpeng Li
2013-07-17 1:26 ` Wanpeng Li
2013-07-15 15:20 ` [PATCH 04/18] mm: numa: Do not migrate or account for hinting faults on the zero page Mel Gorman
2013-07-17 11:00 ` Peter Zijlstra
2013-07-31 8:11 ` Mel Gorman
2013-07-15 15:20 ` [PATCH 05/18] sched: Select a preferred node with the most numa hinting faults Mel Gorman
2013-07-15 15:20 ` [PATCH 06/18] sched: Update NUMA hinting faults once per scan Mel Gorman
2013-07-15 15:20 ` [PATCH 07/18] sched: Favour moving tasks towards the preferred node Mel Gorman
2013-07-25 10:40 ` [PATCH] sched, numa: migrates_degrades_locality() Peter Zijlstra
2013-07-31 8:44 ` Mel Gorman
2013-07-31 8:50 ` Peter Zijlstra
2013-07-15 15:20 ` [PATCH 08/18] sched: Reschedule task on preferred NUMA node once selected Mel Gorman
2013-07-17 1:31 ` Hillf Danton
2013-07-31 9:07 ` Mel Gorman
2013-07-31 9:38 ` Srikar Dronamraju
2013-08-01 4:47 ` Srikar Dronamraju
2013-08-01 15:38 ` Mel Gorman
2013-07-15 15:20 ` [PATCH 09/18] sched: Add infrastructure for split shared/private accounting of NUMA hinting faults Mel Gorman
2013-07-17 2:17 ` Hillf Danton
2013-07-31 9:08 ` Mel Gorman
2013-07-15 15:20 ` [PATCH 10/18] sched: Increase NUMA PTE scanning when a new preferred node is selected Mel Gorman
2013-07-15 15:20 ` [PATCH 11/18] sched: Check current->mm before allocating NUMA faults Mel Gorman
2013-07-15 15:20 ` [PATCH 12/18] sched: Set the scan rate proportional to the size of the task being scanned Mel Gorman
2013-07-15 15:20 ` [PATCH 13/18] mm: numa: Scan pages with elevated page_mapcount Mel Gorman
2013-07-17 5:22 ` Sam Ben
2013-07-31 9:13 ` Mel Gorman
2013-07-15 15:20 ` [PATCH 14/18] sched: Remove check that skips small VMAs Mel Gorman
2013-07-15 15:20 ` [PATCH 15/18] sched: Set preferred NUMA node based on number of private faults Mel Gorman
2013-07-18 1:53 ` [PATCH 15/18] fix compilation with !CONFIG_NUMA_BALANCING Rik van Riel
2013-07-31 9:19 ` Mel Gorman
2013-07-26 11:20 ` [PATCH 15/18] sched: Set preferred NUMA node based on number of private faults Peter Zijlstra
2013-07-31 9:29 ` Mel Gorman
2013-07-31 9:34 ` Peter Zijlstra
2013-07-31 10:10 ` Mel Gorman
2013-07-15 15:20 ` [PATCH 16/18] sched: Avoid overloading CPUs on a preferred NUMA node Mel Gorman
2013-07-15 20:03 ` Peter Zijlstra
2013-07-16 8:23 ` Mel Gorman
2013-07-16 10:35 ` Peter Zijlstra
2013-07-16 15:55 ` Hillf Danton
2013-07-16 16:01 ` Mel Gorman
2013-07-17 10:54 ` Peter Zijlstra
2013-07-31 9:49 ` Mel Gorman
2013-08-01 7:10 ` Srikar Dronamraju
2013-08-01 15:42 ` Mel Gorman
2013-07-15 15:20 ` [PATCH 17/18] sched: Retry migration of tasks to CPU on a preferred node Mel Gorman
2013-07-25 10:33 ` Peter Zijlstra
2013-07-31 10:03 ` Mel Gorman
2013-07-31 10:05 ` Peter Zijlstra
2013-07-31 10:07 ` Mel Gorman
2013-07-25 10:35 ` Peter Zijlstra
2013-08-01 5:13 ` Srikar Dronamraju
2013-08-01 15:46 ` Mel Gorman
2013-07-15 15:20 ` [PATCH 18/18] sched: Swap tasks when reschuling if a CPU on a target node is imbalanced Mel Gorman
2013-07-15 20:11 ` Peter Zijlstra
2013-07-16 9:41 ` Mel Gorman
2013-08-01 4:59 ` Srikar Dronamraju
2013-08-01 15:48 ` Mel Gorman
2013-07-15 20:14 ` [PATCH 0/18] Basic scheduler support for automatic NUMA balancing V5 Peter Zijlstra
2013-07-16 15:10 ` Srikar Dronamraju
2013-07-25 10:36 ` Peter Zijlstra
2013-07-31 10:30 ` Mel Gorman
2013-07-31 10:48 ` Peter Zijlstra
2013-07-31 11:57 ` Mel Gorman
2013-07-31 15:30 ` Peter Zijlstra
2013-07-31 16:11 ` Mel Gorman
2013-07-31 16:39 ` Peter Zijlstra
2013-08-01 15:51 ` Mel Gorman
2013-07-25 10:38 ` [PATCH] mm, numa: Sanitize task_numa_fault() callsites Peter Zijlstra
2013-07-31 11:25 ` Mel Gorman
2013-07-25 10:41 ` Peter Zijlstra [this message]
2013-07-25 10:46 ` [PATCH] mm, sched, numa: Create a per-task MPOL_INTERLEAVE policy Peter Zijlstra
2013-07-26 9:55 ` Peter Zijlstra
2013-08-26 16:10 ` Peter Zijlstra
2013-08-26 16:14 ` Peter Zijlstra
2013-07-30 11:24 ` [PATCH] mm, numa: Change page last {nid,pid} into {cpu,pid} Peter Zijlstra
2013-08-01 22:33 ` Rik van Riel
2013-07-30 11:38 ` [PATCH] sched, numa: Use {cpu, pid} to create task groups for shared faults Peter Zijlstra
2013-07-31 15:07 ` Peter Zijlstra
2013-07-31 15:38 ` Peter Zijlstra
2013-07-31 15:45 ` Don Morris
2013-07-31 16:05 ` Peter Zijlstra
2013-08-02 16:47 ` [PATCH -v3] " Peter Zijlstra
2013-08-02 16:50 ` [PATCH] mm, numa: Do not group on RO pages Peter Zijlstra
2013-08-02 19:56 ` Peter Zijlstra
2013-08-05 19:36 ` [PATCH] numa,sched: use group fault statistics in numa placement Rik van Riel
2013-08-09 13:55 ` Don Morris
2013-08-28 16:41 ` [PATCH -v3] sched, numa: Use {cpu, pid} to create task groups for shared faults Peter Zijlstra
2013-08-28 17:10 ` Rik van Riel
2013-08-01 6:23 ` [PATCH,RFC] numa,sched: use group fault statistics in numa placement Rik van Riel
2013-08-01 10:37 ` Peter Zijlstra
2013-08-01 16:35 ` Rik van Riel
2013-08-01 22:36 ` [RFC PATCH -v2] " Rik van Riel
2013-07-30 13:58 ` [PATCH 0/18] Basic scheduler support for automatic NUMA balancing V5 Andrew Theurer
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