linux-kernel - [PATCH v7 0/1] sched: update the rq->avg_idle when a task is moved to an idle CPU

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Message-ID: <20251226063203.5947-1-shijie8@gmail.com>
Date: Fri, 26 Dec 2025 14:32:02 +0800
From: Huang Shijie <shijie8@...il.com>
To: mingo@...hat.com,
	peterz@...radead.org,
	vincent.guittot@...aro.org
Cc: dietmar.eggemann@....com,
	rostedt@...dmis.org,
	bsegall@...gle.com,
	mgorman@...e.de,
	vschneid@...hat.com,
	linux-kernel@...r.kernel.org,
	vineethr@...ux.ibm.com,
	kprateek.nayak@....com,
	cl@...ux.com,
	Huang Shijie <shijie8@...il.com>
Subject: [PATCH v7 0/1] sched: update the rq->avg_idle when a task is moved to an idle CPU

In the newidle balance, the rq->idle_stamp may set to a non-zero value
if it cannot pull any task.

In the wakeup, it will detect the rq->idle_stamp, and updates
the rq->avg_idle, then ends the CPU idle status by setting rq->idle_stamp
to zero.

Besides the wakeup, current code does not end the CPU idle status
when a task is moved to the idle CPU, such as fork/clone, execve,
or other cases.

This patch set tries to resolve it.


v6--> v7:
    Call the update_rq_avg_idle() in the put_prev_task_idle().
    Remove the patch 1 in the original patch set.
   --v6:https://lkml.org/lkml/2025/12/9/377

v5--> v6:
    Remove "this_rq->idle_stamp = 0;" in patch 1.
    Update the test result with Specjbb.
   --v5:https://lkml.org/lkml/2025/12/3/179

v4--> v5:
    Modify the changelog.

   --v4:https://lkml.org/lkml/2025/11/28/300

v3--> v4:
     Remove the code for delayed task.

   --v3: https://lkml.org/lkml/2025/11/27/456

v2--> v3:
  -- merge patch 3 into patch 2:
      move update_rq_avg_idle() to enqueue_task().

   --v2: https://lkml.org/lkml/2025/11/27/214

v1--> v2:
  -- Put update_rq_avg_idle() to activate_task()
  -- Add Delay-dequeue task check.

   --v1: https://lkml.org/lkml/2025/11/24/97

Huang Shijie (1):
  sched: update the rq->avg_idle when a task is moved to an idle CPU

 kernel/sched/core.c  | 27 +++++++++++++++------------
 kernel/sched/idle.c  |  1 +
 kernel/sched/sched.h |  1 +
 3 files changed, 17 insertions(+), 12 deletions(-)

-- 
2.43.0