From: "tip-bot2 for Vincent Guittot" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Vincent Guittot <vincent.guittot@linaro.org>,
Ben Segall <bsegall@google.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Juri Lelli <juri.lelli@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Mel Gorman <mgorman@suse.de>, Mike Galbraith <efault@gmx.de>,
Morten.Rasmussen@arm.com, Peter Zijlstra <peterz@infradead.org>,
Steven Rostedt <rostedt@goodmis.org>,
Thomas Gleixner <tglx@linutronix.de>,
hdanton@sina.com, parth@linux.ibm.com, pauld@redhat.com,
quentin.perret@arm.com, riel@surriel.com,
srikar@linux.vnet.ibm.com, valentin.schneider@arm.com,
Ingo Molnar <mingo@kernel.org>, Borislav Petkov <bp@alien8.de>,
linux-kernel@vger.kernel.org
Subject: [tip: sched/core] sched/fair: Optimize find_idlest_group()
Date: Mon, 21 Oct 2019 09:12:41 -0000 [thread overview]
Message-ID: <157164916159.29376.11878648032149648593.tip-bot2@tip-bot2> (raw)
In-Reply-To: <1571405198-27570-11-git-send-email-vincent.guittot@linaro.org>
The following commit has been merged into the sched/core branch of tip:
Commit-ID: fc1273f4cefe6670d528715581c848abf64f391c
Gitweb: https://git.kernel.org/tip/fc1273f4cefe6670d528715581c848abf64f391c
Author: Vincent Guittot <vincent.guittot@linaro.org>
AuthorDate: Fri, 18 Oct 2019 15:26:37 +02:00
Committer: Ingo Molnar <mingo@kernel.org>
CommitterDate: Mon, 21 Oct 2019 09:40:55 +02:00
sched/fair: Optimize find_idlest_group()
find_idlest_group() now reads CPU's load_avg in two different ways.
Consolidate the function to read and use load_avg only once and simplify
the algorithm to only look for the group with lowest load_avg.
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Ben Segall <bsegall@google.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Morten.Rasmussen@arm.com
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: hdanton@sina.com
Cc: parth@linux.ibm.com
Cc: pauld@redhat.com
Cc: quentin.perret@arm.com
Cc: riel@surriel.com
Cc: srikar@linux.vnet.ibm.com
Cc: valentin.schneider@arm.com
Link: https://lkml.kernel.org/r/1571405198-27570-11-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/sched/fair.c | 50 ++++++++++++--------------------------------
1 file changed, 14 insertions(+), 36 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index b0703b4..95a57c7 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5550,16 +5550,14 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p,
{
struct sched_group *idlest = NULL, *group = sd->groups;
struct sched_group *most_spare_sg = NULL;
- unsigned long min_runnable_load = ULONG_MAX;
- unsigned long this_runnable_load = ULONG_MAX;
- unsigned long min_avg_load = ULONG_MAX, this_avg_load = ULONG_MAX;
+ unsigned long min_load = ULONG_MAX, this_load = ULONG_MAX;
unsigned long most_spare = 0, this_spare = 0;
int imbalance_scale = 100 + (sd->imbalance_pct-100)/2;
unsigned long imbalance = scale_load_down(NICE_0_LOAD) *
(sd->imbalance_pct-100) / 100;
do {
- unsigned long load, avg_load, runnable_load;
+ unsigned long load;
unsigned long spare_cap, max_spare_cap;
int local_group;
int i;
@@ -5576,15 +5574,11 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p,
* Tally up the load of all CPUs in the group and find
* the group containing the CPU with most spare capacity.
*/
- avg_load = 0;
- runnable_load = 0;
+ load = 0;
max_spare_cap = 0;
for_each_cpu(i, sched_group_span(group)) {
- load = cpu_load(cpu_rq(i));
- runnable_load += load;
-
- avg_load += cfs_rq_load_avg(&cpu_rq(i)->cfs);
+ load += cpu_load(cpu_rq(i));
spare_cap = capacity_spare_without(i, p);
@@ -5593,31 +5587,15 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p,
}
/* Adjust by relative CPU capacity of the group */
- avg_load = (avg_load * SCHED_CAPACITY_SCALE) /
- group->sgc->capacity;
- runnable_load = (runnable_load * SCHED_CAPACITY_SCALE) /
+ load = (load * SCHED_CAPACITY_SCALE) /
group->sgc->capacity;
if (local_group) {
- this_runnable_load = runnable_load;
- this_avg_load = avg_load;
+ this_load = load;
this_spare = max_spare_cap;
} else {
- if (min_runnable_load > (runnable_load + imbalance)) {
- /*
- * The runnable load is significantly smaller
- * so we can pick this new CPU:
- */
- min_runnable_load = runnable_load;
- min_avg_load = avg_load;
- idlest = group;
- } else if ((runnable_load < (min_runnable_load + imbalance)) &&
- (100*min_avg_load > imbalance_scale*avg_load)) {
- /*
- * The runnable loads are close so take the
- * blocked load into account through avg_load:
- */
- min_avg_load = avg_load;
+ if (load < min_load) {
+ min_load = load;
idlest = group;
}
@@ -5658,18 +5636,18 @@ skip_spare:
* local domain to be very lightly loaded relative to the remote
* domains but "imbalance" skews the comparison making remote CPUs
* look much more favourable. When considering cross-domain, add
- * imbalance to the runnable load on the remote node and consider
- * staying local.
+ * imbalance to the load on the remote node and consider staying
+ * local.
*/
if ((sd->flags & SD_NUMA) &&
- min_runnable_load + imbalance >= this_runnable_load)
+ min_load + imbalance >= this_load)
return NULL;
- if (min_runnable_load > (this_runnable_load + imbalance))
+ if (min_load >= this_load + imbalance)
return NULL;
- if ((this_runnable_load < (min_runnable_load + imbalance)) &&
- (100*this_avg_load < imbalance_scale*min_avg_load))
+ if ((this_load < (min_load + imbalance)) &&
+ (100*this_load < imbalance_scale*min_load))
return NULL;
return idlest;
next prev parent reply other threads:[~2019-10-21 9:13 UTC|newest]
Thread overview: 89+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-18 13:26 [PATCH v4 00/10] sched/fair: rework the CFS load balance Vincent Guittot
2019-10-18 13:26 ` [PATCH v4 01/11] sched/fair: clean up asym packing Vincent Guittot
2019-10-21 9:12 ` [tip: sched/core] sched/fair: Clean " tip-bot2 for Vincent Guittot
2019-10-30 14:51 ` [PATCH v4 01/11] sched/fair: clean " Mel Gorman
2019-10-30 16:03 ` Vincent Guittot
2019-10-18 13:26 ` [PATCH v4 02/11] sched/fair: rename sum_nr_running to sum_h_nr_running Vincent Guittot
2019-10-21 9:12 ` [tip: sched/core] sched/fair: Rename sg_lb_stats::sum_nr_running " tip-bot2 for Vincent Guittot
2019-10-30 14:53 ` [PATCH v4 02/11] sched/fair: rename sum_nr_running " Mel Gorman
2019-10-18 13:26 ` [PATCH v4 03/11] sched/fair: remove meaningless imbalance calculation Vincent Guittot
2019-10-21 9:12 ` [tip: sched/core] sched/fair: Remove " tip-bot2 for Vincent Guittot
2019-10-18 13:26 ` [PATCH v4 04/11] sched/fair: rework load_balance Vincent Guittot
2019-10-21 9:12 ` [tip: sched/core] sched/fair: Rework load_balance() tip-bot2 for Vincent Guittot
2019-10-30 15:45 ` [PATCH v4 04/11] sched/fair: rework load_balance Mel Gorman
2019-10-30 16:16 ` Valentin Schneider
2019-10-31 9:09 ` Vincent Guittot
2019-10-31 10:15 ` Mel Gorman
2019-10-31 11:13 ` Vincent Guittot
2019-10-31 11:40 ` Mel Gorman
2019-11-08 16:35 ` Vincent Guittot
2019-11-08 18:37 ` Mel Gorman
2019-11-12 10:58 ` Vincent Guittot
2019-11-12 15:06 ` Mel Gorman
2019-11-12 15:40 ` Vincent Guittot
2019-11-12 17:45 ` Mel Gorman
2019-11-18 13:50 ` Ingo Molnar
2019-11-18 13:57 ` Vincent Guittot
2019-11-18 14:51 ` Mel Gorman
2019-10-18 13:26 ` [PATCH v4 05/11] sched/fair: use rq->nr_running when balancing load Vincent Guittot
2019-10-21 9:12 ` [tip: sched/core] sched/fair: Use " tip-bot2 for Vincent Guittot
2019-10-30 15:54 ` [PATCH v4 05/11] sched/fair: use " Mel Gorman
2019-10-18 13:26 ` [PATCH v4 06/11] sched/fair: use load instead of runnable load in load_balance Vincent Guittot
2019-10-21 9:12 ` [tip: sched/core] sched/fair: Use load instead of runnable load in load_balance() tip-bot2 for Vincent Guittot
2019-10-30 15:58 ` [PATCH v4 06/11] sched/fair: use load instead of runnable load in load_balance Mel Gorman
2019-10-18 13:26 ` [PATCH v4 07/11] sched/fair: evenly spread tasks when not overloaded Vincent Guittot
2019-10-21 9:12 ` [tip: sched/core] sched/fair: Spread out tasks evenly " tip-bot2 for Vincent Guittot
2019-10-30 16:03 ` [PATCH v4 07/11] sched/fair: evenly spread tasks " Mel Gorman
2019-10-18 13:26 ` [PATCH v4 08/11] sched/fair: use utilization to select misfit task Vincent Guittot
2019-10-21 9:12 ` [tip: sched/core] sched/fair: Use " tip-bot2 for Vincent Guittot
2019-10-18 13:26 ` [PATCH v4 09/11] sched/fair: use load instead of runnable load in wakeup path Vincent Guittot
2019-10-21 9:12 ` [tip: sched/core] sched/fair: Use " tip-bot2 for Vincent Guittot
2019-10-18 13:26 ` [PATCH v4 10/11] sched/fair: optimize find_idlest_group Vincent Guittot
2019-10-21 9:12 ` tip-bot2 for Vincent Guittot [this message]
2019-10-18 13:26 ` [PATCH v4 11/11] sched/fair: rework find_idlest_group Vincent Guittot
2019-10-21 9:12 ` [tip: sched/core] sched/fair: Rework find_idlest_group() tip-bot2 for Vincent Guittot
2019-10-22 16:46 ` [PATCH] sched/fair: fix rework of find_idlest_group() Vincent Guittot
2019-10-23 7:50 ` Chen, Rong A
2019-10-30 16:07 ` Mel Gorman
2019-11-18 17:42 ` [tip: sched/core] sched/fair: Fix " tip-bot2 for Vincent Guittot
2019-11-22 14:37 ` [PATCH] sched/fair: fix " Valentin Schneider
2019-11-25 9:16 ` Vincent Guittot
2019-11-25 11:03 ` Valentin Schneider
2019-11-20 11:58 ` [PATCH v4 11/11] sched/fair: rework find_idlest_group Qais Yousef
2019-11-20 13:21 ` Vincent Guittot
2019-11-20 16:53 ` Vincent Guittot
2019-11-20 17:34 ` Qais Yousef
2019-11-20 17:43 ` Vincent Guittot
2019-11-20 18:10 ` Qais Yousef
2019-11-20 18:20 ` Vincent Guittot
2019-11-20 18:27 ` Qais Yousef
2019-11-20 19:28 ` Vincent Guittot
2019-11-20 19:55 ` Qais Yousef
2019-11-21 14:58 ` Qais Yousef
2019-11-22 14:34 ` Valentin Schneider
2019-11-25 9:59 ` Vincent Guittot
2019-11-25 11:13 ` Valentin Schneider
2019-10-21 7:50 ` [PATCH v4 00/10] sched/fair: rework the CFS load balance Ingo Molnar
2019-10-21 8:44 ` Vincent Guittot
2019-10-21 12:56 ` Phil Auld
2019-10-24 12:38 ` Phil Auld
2019-10-24 13:46 ` Phil Auld
2019-10-24 14:59 ` Vincent Guittot
2019-10-25 13:33 ` Phil Auld
2019-10-28 13:03 ` Vincent Guittot
2019-10-30 14:39 ` Phil Auld
2019-10-30 16:24 ` Dietmar Eggemann
2019-10-30 16:35 ` Valentin Schneider
2019-10-30 17:19 ` Phil Auld
2019-10-30 17:25 ` Valentin Schneider
2019-10-30 17:29 ` Phil Auld
2019-10-30 17:28 ` Vincent Guittot
2019-10-30 17:44 ` Phil Auld
2019-10-30 17:25 ` Vincent Guittot
2019-10-31 13:57 ` Phil Auld
2019-10-31 16:41 ` Vincent Guittot
2019-10-30 16:24 ` Mel Gorman
2019-10-30 16:35 ` Vincent Guittot
2019-11-18 13:15 ` Ingo Molnar
2019-11-25 12:48 ` Valentin Schneider
2020-01-03 16:39 ` Valentin Schneider
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