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From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To: Ingo Molnar <mingo@kernel.org>, Peter Zijlstra <peterz@infradead.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Mel Gorman <mgorman@techsingularity.net>,
	Rik van Riel <riel@surriel.com>,
	Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: [PATCH 18/19] sched/numa: Reset scan rate whenever task moves across nodes
Date: Mon,  4 Jun 2018 15:30:27 +0530	[thread overview]
Message-ID: <1528106428-19992-19-git-send-email-srikar@linux.vnet.ibm.com> (raw)
In-Reply-To: <1528106428-19992-1-git-send-email-srikar@linux.vnet.ibm.com>

Currently task scan rate is reset when numa balancer migrates the task
to a different node. If numa balancer initiates a swap, reset is only
applicable to the task that initiates the swap. Similarly no scan rate
reset is done if the task is migrated across nodes by traditional load
balancer.

Instead move the scan reset to the migrate_task_rq. This ensures the
task moved out of its preferred node, either gets back to its preferred
node quickly or finds a new preferred node. Doing so, would be fair to
all tasks migrating across nodes.


Testcase       Time:         Min         Max         Avg      StdDev
numa01.sh      Real:      428.48      837.17      700.45      162.77
numa01.sh       Sys:       78.64      247.70      164.45       58.32
numa01.sh      User:    37487.25    63728.06    54399.27    10088.13
numa02.sh      Real:       60.07       62.65       61.41        0.85
numa02.sh       Sys:       15.83       29.36       21.04        4.48
numa02.sh      User:     5194.27     5280.60     5236.55       28.01
numa03.sh      Real:      814.33      881.93      849.69       27.06
numa03.sh       Sys:      111.45      134.02      125.28        7.69
numa03.sh      User:    63007.36    68013.46    65590.46     2023.37
numa04.sh      Real:      412.19      438.75      424.43        9.28
numa04.sh       Sys:      232.97      315.77      268.98       26.98
numa04.sh      User:    33997.30    35292.88    34711.66      415.78
numa05.sh      Real:      394.88      449.45      424.30       22.53
numa05.sh       Sys:      262.03      390.10      314.53       51.01
numa05.sh      User:    33389.03    35684.40    34561.34      942.34

Testcase       Time:         Min         Max         Avg      StdDev 	 %Change
numa01.sh      Real:      449.46      770.77      615.22      101.70 	 13.85%
numa01.sh       Sys:      132.72      208.17      170.46       24.96 	 -3.52%
numa01.sh      User:    39185.26    60290.89    50066.76     6807.84 	 8.653%
numa02.sh      Real:       60.85       61.79       61.28        0.37 	 0.212%
numa02.sh       Sys:       15.34       24.71       21.08        3.61 	 -0.18%
numa02.sh      User:     5204.41     5249.85     5231.21       17.60 	 0.102%
numa03.sh      Real:      785.50      916.97      840.77       44.98 	 1.060%
numa03.sh       Sys:      108.08      133.60      119.43        8.82 	 4.898%
numa03.sh      User:    61422.86    70919.75    64720.87     3310.61 	 1.343%
numa04.sh      Real:      429.57      587.37      480.80       57.40 	 -11.7%
numa04.sh       Sys:      240.61      321.97      290.84       33.58 	 -7.51%
numa04.sh      User:    34597.65    40498.99    37079.48     2060.72 	 -6.38%
numa05.sh      Real:      392.09      431.25      414.65       13.82 	 2.327%
numa05.sh       Sys:      229.41      372.48      297.54       53.14 	 5.710%
numa05.sh      User:    33390.86    34697.49    34222.43      556.42 	 0.990%

Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
 kernel/sched/fair.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 339c3dc..fc1f388 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1808,12 +1808,6 @@ static int task_numa_migrate(struct task_struct *p)
 	if (env.best_cpu == -1)
 		return -EAGAIN;
 
-	/*
-	 * Reset the scan period if the task is being rescheduled on an
-	 * alternative node to recheck if the tasks is now properly placed.
-	 */
-	p->numa_scan_period = task_scan_start(p);
-
 	best_rq = cpu_rq(env.best_cpu);
 	if (env.best_task == NULL) {
 		pg_data_t *pgdat = NODE_DATA(cpu_to_node(env.dst_cpu));
@@ -6669,6 +6663,19 @@ static void migrate_task_rq_fair(struct task_struct *p, int new_cpu __maybe_unus
 
 	/* We have migrated, no longer consider this task hot */
 	p->se.exec_start = 0;
+
+#ifdef CONFIG_NUMA_BALANCING
+	if (!p->mm || (p->flags & PF_EXITING))
+		return;
+
+	if (p->numa_faults) {
+		int src_nid = cpu_to_node(task_cpu(p));
+		int dst_nid = cpu_to_node(new_cpu);
+
+		if (src_nid != dst_nid)
+			p->numa_scan_period = task_scan_start(p);
+	}
+#endif
 }
 
 static void task_dead_fair(struct task_struct *p)
-- 
1.8.3.1

  parent reply	other threads:[~2018-06-04 10:02 UTC|newest]

Thread overview: 66+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-04 10:00 [PATCH 00/19] Fixes for sched/numa_balancing Srikar Dronamraju
2018-06-04 10:00 ` [PATCH 01/19] sched/numa: Remove redundant field Srikar Dronamraju
2018-06-04 14:53   ` Rik van Riel
2018-06-05  8:41   ` Mel Gorman
2018-06-04 10:00 ` [PATCH 02/19] sched/numa: Evaluate move once per node Srikar Dronamraju
2018-06-04 14:51   ` Rik van Riel
2018-06-04 15:45     ` Srikar Dronamraju
2018-06-04 10:00 ` [PATCH 03/19] sched/numa: Simplify load_too_imbalanced Srikar Dronamraju
2018-06-04 14:57   ` Rik van Riel
2018-06-05  8:46   ` Mel Gorman
2018-06-04 10:00 ` [PATCH 04/19] sched/numa: Set preferred_node based on best_cpu Srikar Dronamraju
2018-06-04 12:18   ` Peter Zijlstra
2018-06-04 12:53     ` Srikar Dronamraju
2018-06-04 12:23   ` Peter Zijlstra
2018-06-04 12:59     ` Srikar Dronamraju
2018-06-04 13:39       ` Peter Zijlstra
2018-06-04 13:48         ` Srikar Dronamraju
2018-06-04 14:37       ` Rik van Riel
2018-06-04 15:56         ` Srikar Dronamraju
2018-06-04 10:00 ` [PATCH 05/19] sched/numa: Use task faults only if numa_group is not yet setup Srikar Dronamraju
2018-06-04 12:24   ` Peter Zijlstra
2018-06-04 13:09     ` Srikar Dronamraju
2018-06-04 10:00 ` [PATCH 06/19] sched/debug: Reverse the order of printing faults Srikar Dronamraju
2018-06-04 16:28   ` Rik van Riel
2018-06-05  8:50   ` Mel Gorman
2018-06-04 10:00 ` [PATCH 07/19] sched/numa: Skip nodes that are at hoplimit Srikar Dronamraju
2018-06-04 16:27   ` Rik van Riel
2018-06-05  8:50   ` Mel Gorman
2018-06-04 10:00 ` [PATCH 08/19] sched/numa: Remove unused task_capacity from numa_stats Srikar Dronamraju
2018-06-04 16:28   ` Rik van Riel
2018-06-05  8:57   ` Mel Gorman
2018-06-04 10:00 ` [PATCH 09/19] sched/numa: Modify migrate_swap to accept additional params Srikar Dronamraju
2018-06-04 17:00   ` Rik van Riel
2018-06-05  8:58   ` Mel Gorman
2018-06-04 10:00 ` [PATCH 10/19] sched/numa: Stop multiple tasks from moving to the cpu at the same time Srikar Dronamraju
2018-06-04 17:57   ` Rik van Riel
2018-06-05  9:51   ` Mel Gorman
2018-06-04 10:00 ` [PATCH 11/19] sched/numa: Restrict migrating in parallel to the same node Srikar Dronamraju
2018-06-04 17:59   ` Rik van Riel
2018-06-05  9:53   ` Mel Gorman
2018-06-06 12:58     ` Srikar Dronamraju
2018-06-04 10:00 ` [PATCH 12/19] sched:numa Remove numa_has_capacity Srikar Dronamraju
2018-06-04 18:07   ` Rik van Riel
2018-06-04 10:00 ` [PATCH 13/19] mm/migrate: Use xchg instead of spinlock Srikar Dronamraju
2018-06-04 18:22   ` Rik van Riel
2018-06-04 19:28   ` Peter Zijlstra
2018-06-05  7:24     ` Srikar Dronamraju
2018-06-05  8:16       ` Peter Zijlstra
2018-06-04 10:00 ` [PATCH 14/19] sched/numa: Updation of scan period need not be in lock Srikar Dronamraju
2018-06-04 18:24   ` Rik van Riel
2018-06-04 10:00 ` [PATCH 15/19] sched/numa: Use group_weights to identify if migration degrades locality Srikar Dronamraju
2018-06-04 18:56   ` Rik van Riel
2018-06-04 10:00 ` [PATCH 16/19] sched/numa: Detect if node actively handling migration Srikar Dronamraju
2018-06-04 20:05   ` Rik van Riel
2018-06-05  3:56     ` Srikar Dronamraju
2018-06-05 13:07       ` Rik van Riel
2018-06-06 12:55         ` Srikar Dronamraju
2018-06-06 13:55           ` Rik van Riel
2018-06-06 15:32             ` Srikar Dronamraju
2018-06-06 17:06               ` Rik van Riel
2018-06-04 10:00 ` [PATCH 17/19] sched/numa: Pass destination cpu as a parameter to migrate_task_rq Srikar Dronamraju
2018-06-04 10:00 ` Srikar Dronamraju [this message]
2018-06-04 20:08   ` [PATCH 18/19] sched/numa: Reset scan rate whenever task moves across nodes Rik van Riel
2018-06-05  9:58   ` Mel Gorman
2018-06-06 13:47     ` Srikar Dronamraju
2018-06-04 10:00 ` [PATCH 19/19] sched/numa: Move task_placement closer to numa_migrate_preferred Srikar Dronamraju

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