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From: Fernand Sieber <sieberf@amazon.com>
To: <mingo@redhat.com>, <peterz@infradead.org>
Cc: <linux-kernel@vger.kernel.org>, <juri.lelli@redhat.com>,
	<vincent.guittot@linaro.org>, <dietmar.eggemann@arm.com>,
	<rostedt@goodmis.org>, <bsegall@google.com>, <mgorman@suse.de>,
	<bristot@redhat.com>, <vschneid@redhat.com>, <dwmw@amazon.co.uk>,
	<jschoenh@amazon.de>, <liuyuxua@amazon.com>, <graf@amazon.de>
Subject: [PATCH 0/4] sched/fair: Core sched wake up path improvements
Date: Mon, 22 Sep 2025 14:39:21 +0200	[thread overview]
Message-ID: <cover.1758543008.git.sieberf@amazon.com> (raw)

This patch series addresses several issues and improvements in the core
scheduling within the fair scheduler's wake-up paths. The overall result
is better task placement reducing force idle.

The main issues addressed are as follows:

Slow path:
1. Fix incorrect cookie matching logic that wrongly discards idle cores
2. Better fallback logic when no cookie matching target is found

Fast path:
3. Add cookie checks in wake affine idle to prevent force idle
4. Enhance task selection in select idle sibling to consider cookies

Fernand Sieber (4):
  sched/fair: Fix cookie check on __select_idle_cpu()
  sched/fair: Still look for the idlest cpu with no matching cookie
  sched/fair: Add cookie checks on wake idle path
  sched/fair: Add more core cookie check in wake up fast path

 kernel/sched/fair.c  | 49 ++++++++++++++++++++++++++++++++------------
 kernel/sched/sched.h | 41 ++++++++++++++++++++----------------
 2 files changed, 59 insertions(+), 31 deletions(-)

--
2.43.0




Amazon Development Centre (South Africa) (Proprietary) Limited
29 Gogosoa Street, Observatory, Cape Town, Western Cape, 7925, South Africa
Registration Number: 2004 / 034463 / 07


             reply	other threads:[~2025-09-22 12:40 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-09-22 12:39 Fernand Sieber [this message]
2025-09-22 12:39 ` [PATCH 1/4] sched/fair: Fix cookie check on __select_idle_cpu() Fernand Sieber
2025-09-23  8:42   ` K Prateek Nayak
2025-09-25  6:35     ` Madadi Vineeth Reddy
2025-09-22 12:39 ` [PATCH 2/4] sched/fair: Still look for the idlest cpu with no matching cookie Fernand Sieber
2025-09-23  1:51   ` K Prateek Nayak
2025-09-23  7:32     ` Fernand Sieber
2025-09-23  7:44       ` Fernand Sieber
2025-09-22 12:39 ` [PATCH 3/4] sched/fair: Add cookie checks on wake idle path Fernand Sieber
2025-09-22 12:39 ` [PATCH 4/4] sched/fair: Add more core cookie check in wake up fast path Fernand Sieber
2025-09-23  8:55   ` K Prateek Nayak
2025-09-23  9:30     ` Fernand Sieber
2025-09-24  4:21       ` K Prateek Nayak
2025-11-05 15:34         ` [PATCH 4/4] sched/fair: Add more core cookie check in wake up Fernand Sieber
2025-11-20 10:30         ` [PATCH 4/4] sched/fair: Add more core cookie check in wake up fast path Fernand Sieber

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