From: Peter Zijlstra <peterz@infradead.org>
To: Rik van Riel <riel@redhat.com>
Cc: linux-kernel@vger.kernel.org, chegu_vinod@hp.com,
mgorman@suse.de, mingo@kernel.org
Subject: Re: [PATCH 9/7] sched,numa: remove task_h_load from task_numa_compare
Date: Wed, 25 Jun 2014 07:21:44 +0200 [thread overview]
Message-ID: <20140625052144.GH3588@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20140625050735.GB28774@twins.programming.kicks-ass.net>
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On Wed, Jun 25, 2014 at 07:07:35AM +0200, Peter Zijlstra wrote:
> Shall I merge this into patch 3?
Which gets me the below; which is has a wrong changelog.
task_h_load() already computes the load as seen from the root group.
effective_load() just does a better (and more expensive) job of
computing the task movement implications of a move.
So the total effect of this patch shouldn't be very big; regular load
balancing also only uses task_h_load(), see move_tasks().
Now, we don't run with preemption disabled, don't run as often, etc..,
so maybe we can indeed use the more expensive variant just fine, but
does it really matter?
---
Subject: sched,numa: use effective_load to balance NUMA loads
From: Rik van Riel <riel@redhat.com>
Date: Mon, 23 Jun 2014 11:46:14 -0400
When CONFIG_FAIR_GROUP_SCHED is enabled, the load that a task places
on a CPU is determined by the group the task is in. This is conveniently
calculated for us by effective_load(), which task_numa_compare should
use.
The active groups on the source and destination CPU can be different,
so the calculation needs to be done separately for each CPU.
Cc: mgorman@suse.de
Cc: mingo@kernel.org
Cc: chegu_vinod@hp.com
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1403538378-31571-3-git-send-email-riel@redhat.com
---
kernel/sched/fair.c | 20 ++++++++++++++------
1 file changed, 14 insertions(+), 6 deletions(-)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1151,6 +1151,7 @@ static void task_numa_compare(struct tas
struct rq *src_rq = cpu_rq(env->src_cpu);
struct rq *dst_rq = cpu_rq(env->dst_cpu);
struct task_struct *cur;
+ struct task_group *tg;
long src_load, dst_load;
long load;
long imp = (groupimp > 0) ? groupimp : taskimp;
@@ -1225,14 +1226,21 @@ static void task_numa_compare(struct tas
* In the overloaded case, try and keep the load balanced.
*/
balance:
- load = task_h_load(env->p);
- dst_load = env->dst_stats.load + load;
- src_load = env->src_stats.load - load;
+ src_load = env->src_stats.load;
+ dst_load = env->dst_stats.load;
+
+ /* Calculate the effect of moving env->p from src to dst. */
+ load = env->p->se.load.weight;
+ tg = task_group(env->p);
+ src_load += effective_load(tg, env->src_cpu, -load, -load);
+ dst_load += effective_load(tg, env->dst_cpu, load, load);
if (cur) {
- load = task_h_load(cur);
- dst_load -= load;
- src_load += load;
+ /* Cur moves in the opposite direction. */
+ load = cur->se.load.weight;
+ tg = task_group(cur);
+ src_load += effective_load(tg, env->src_cpu, load, load);
+ dst_load += effective_load(tg, env->dst_cpu, -load, -load);
}
if (load_too_imbalanced(src_load, dst_load, env))
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next prev parent reply other threads:[~2014-06-25 5:22 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-23 15:41 [PATCH 0/7] sched,numa: improve NUMA convergence times riel
2014-06-23 15:41 ` [PATCH 1/7] sched,numa: use group's max nid as task's preferred nid riel
2014-06-25 10:31 ` Mel Gorman
2014-07-05 10:44 ` [tip:sched/core] sched/numa: Use group's max nid as task' s " tip-bot for Rik van Riel
2014-06-23 15:41 ` [PATCH 3/7] sched,numa: use effective_load to balance NUMA loads riel
2014-06-23 15:41 ` [PATCH 4/7] sched,numa: simplify task_numa_compare riel
2014-06-25 10:39 ` Mel Gorman
2014-06-23 15:41 ` [PATCH 5/7] sched,numa: examine a task move when examining a task swap riel
2014-06-23 15:41 ` [PATCH 6/7] sched,numa: rework best node setting in task_numa_migrate riel
2014-07-05 10:45 ` [tip:sched/core] sched/numa: Rework best node setting in task_numa_migrate() tip-bot for Rik van Riel
2014-06-23 15:41 ` [PATCH 7/7] sched,numa: change scan period code to match intent riel
2014-06-25 10:19 ` Mel Gorman
2014-07-05 10:45 ` [tip:sched/core] sched/numa: Change " tip-bot for Rik van Riel
2014-06-23 22:30 ` [PATCH 8/7] sched,numa: do not let a move increase the imbalance Rik van Riel
2014-06-24 14:38 ` Peter Zijlstra
2014-06-24 15:30 ` Rik van Riel
2014-06-25 1:57 ` Rik van Riel
2014-06-24 19:14 ` [PATCH 9/7] sched,numa: remove task_h_load from task_numa_compare Rik van Riel
2014-06-25 5:07 ` Peter Zijlstra
2014-06-25 5:09 ` Rik van Riel
2014-06-25 5:21 ` Peter Zijlstra [this message]
2014-06-25 5:25 ` Rik van Riel
2014-06-25 5:31 ` Peter Zijlstra
2014-06-25 5:39 ` Rik van Riel
2014-06-25 5:57 ` Peter Zijlstra
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