linux-kernel - [PATCH V2] sched: Introduce util

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Date:   Mon, 25 Apr 2022 04:46:51 -0700
From:   Qing Wang <wangqing@...o.com>
To:     Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Juri Lelli <juri.lelli@...hat.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Dietmar Eggemann <dietmar.eggemann@....com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>,
        Daniel Bristot de Oliveira <bristot@...hat.com>,
        linux-kernel@...r.kernel.org
Cc:     Wang Qing <wangqing@...o.com>
Subject: [PATCH V2] sched: Introduce util_est boost

From: Wang Qing <wangqing@...o.com>

Util_avg is greater than util_est means there is a sudden increase in
tasks at this time, we should give it an increment to make load balancing
faster.

Signed-off-by: Wang Qing <wangqing@...o.com>
---
v2:
- modify the return value if UTIL_EST_BOOST is false
---
 kernel/sched/fair.c     | 8 +++++++-
 kernel/sched/features.h | 1 +
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 265bf7a75a37..2fcda7972057 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4036,7 +4036,13 @@ static inline unsigned long _task_util_est(struct task_struct *p)
 
 static inline unsigned long task_util_est(struct task_struct *p)
 {
-	return max(task_util(p), _task_util_est(p));
+	unsigned long util_avg = task_util(p);
+	unsigned long util_est = _task_util_est(p);
+
+	if (sched_feat(UTIL_EST_BOOST) && util_est && util_avg > util_est)
+		return util_avg + (util_avg - util_est)/2;
+	else
+		return max(util_avg, util_est);
 }
 
 #ifdef CONFIG_UCLAMP_TASK
diff --git a/kernel/sched/features.h b/kernel/sched/features.h
index 1cf435bbcd9c..c73a898e7e38 100644
--- a/kernel/sched/features.h
+++ b/kernel/sched/features.h
@@ -95,6 +95,7 @@ SCHED_FEAT(WA_BIAS, true)
  */
 SCHED_FEAT(UTIL_EST, true)
 SCHED_FEAT(UTIL_EST_FASTUP, true)
+SCHED_FEAT(UTIL_EST_BOOST, false)
 
 SCHED_FEAT(LATENCY_WARN, false)
 
-- 
2.27.0.windows.1