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 04/19] sched/numa: Set preferred_node based on best_cpu
Date: Mon, 4 Jun 2018 15:30:13 +0530 [thread overview]
Message-ID: <1528106428-19992-5-git-send-email-srikar@linux.vnet.ibm.com> (raw)
In-Reply-To: <1528106428-19992-1-git-send-email-srikar@linux.vnet.ibm.com>
Currently preferred node is set to dst_nid which is the last node in the
iteration whose group weight or task weight is greater than the current
node. However it doesn't guarantee that dst_nid has the numa capacity
to move. It also doesn't guarantee that dst_nid has the best_cpu which
is the cpu/node ideal for node migration.
Lets consider faults on a 4 node system with group weight numbers
in different nodes being in 0 < 1 < 2 < 3 proportion. Consider the task
is running on 3 and 0 is its preferred node but its capacity is full.
Consider nodes 1, 2 and 3 have capacity. Then the task should be
migrated to node 1. Currently the task gets moved to node 2. env.dst_nid
points to the last node whose faults were greater than current node.
Modify to set the preferred node based of best_cpu.
Also while modifying task_numa_migrate(), use sched_setnuma to set
preferred node. This ensures out numa accounting is correct.
Testcase Time: Min Max Avg StdDev
numa01.sh Real: 435.78 653.81 534.58 83.20
numa01.sh Sys: 121.93 187.18 145.90 23.47
numa01.sh User: 37082.81 51402.80 43647.60 5409.75
numa02.sh Real: 60.64 61.63 61.19 0.40
numa02.sh Sys: 14.72 25.68 19.06 4.03
numa02.sh User: 5210.95 5266.69 5233.30 20.82
numa03.sh Real: 746.51 808.24 780.36 23.88
numa03.sh Sys: 97.26 108.48 105.07 4.28
numa03.sh User: 58956.30 61397.05 60162.95 1050.82
numa04.sh Real: 465.97 519.27 484.81 19.62
numa04.sh Sys: 304.43 359.08 334.68 20.64
numa04.sh User: 37544.16 41186.15 39262.44 1314.91
numa05.sh Real: 411.57 457.20 433.29 16.58
numa05.sh Sys: 230.05 435.48 339.95 67.58
numa05.sh User: 33325.54 36896.31 35637.84 1222.64
Testcase Time: Min Max Avg StdDev %Change
numa01.sh Real: 506.35 794.46 599.06 104.26 -10.76%
numa01.sh Sys: 150.37 223.56 195.99 24.94 -25.55%
numa01.sh User: 43450.69 61752.04 49281.50 6635.33 -11.43%
numa02.sh Real: 60.33 62.40 61.31 0.90 -0.195%
numa02.sh Sys: 18.12 31.66 24.28 5.89 -21.49%
numa02.sh User: 5203.91 5325.32 5260.29 49.98 -0.513%
numa03.sh Real: 696.47 853.62 745.80 57.28 4.6339%
numa03.sh Sys: 85.68 123.71 97.89 13.48 7.3347%
numa03.sh User: 55978.45 66418.63 59254.94 3737.97 1.5323%
numa04.sh Real: 444.05 514.83 497.06 26.85 -2.464%
numa04.sh Sys: 230.39 375.79 316.23 48.58 5.8343%
numa04.sh User: 35403.12 41004.10 39720.80 2163.08 -1.153%
numa05.sh Real: 423.09 460.41 439.57 13.92 -1.428%
numa05.sh Sys: 287.38 480.15 369.37 68.52 -7.964%
numa05.sh User: 34732.12 38016.80 36255.85 1070.51 -1.704%
While there is a performance hit, this is a correctness issue that is very
much needed in bigger systems.
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
kernel/sched/fair.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index ea32a66..94091e6 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1725,8 +1725,9 @@ static int task_numa_migrate(struct task_struct *p)
* Tasks that are "trapped" in such domains cannot be migrated
* elsewhere, so there is no point in (re)trying.
*/
- if (unlikely(!sd)) {
- p->numa_preferred_nid = task_node(p);
+ if (unlikely(!sd) && p->numa_preferred_nid != task_node(p)) {
+ /* Set the new preferred node */
+ sched_setnuma(p, task_node(p));
return -EINVAL;
}
@@ -1785,15 +1786,13 @@ static int task_numa_migrate(struct task_struct *p)
* trying for a better one later. Do not set the preferred node here.
*/
if (p->numa_group) {
- struct numa_group *ng = p->numa_group;
-
if (env.best_cpu == -1)
nid = env.src_nid;
else
- nid = env.dst_nid;
+ nid = cpu_to_node(env.best_cpu);
- if (ng->active_nodes > 1 && numa_is_active_node(env.dst_nid, ng))
- sched_setnuma(p, env.dst_nid);
+ if (nid != p->numa_preferred_nid)
+ sched_setnuma(p, nid);
}
/* No better CPU than the current one was found. */
--
1.8.3.1
next prev parent reply other threads:[~2018-06-04 10:05 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 ` Srikar Dronamraju [this message]
2018-06-04 12:18 ` [PATCH 04/19] sched/numa: Set preferred_node based on best_cpu 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 ` [PATCH 18/19] sched/numa: Reset scan rate whenever task moves across nodes Srikar Dronamraju
2018-06-04 20:08 ` 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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