Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Tianchen Ding <dtcccc@linux.alibaba.com>
To:     Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Juri Lelli <juri.lelli@redhat.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
        Daniel Bristot de Oliveira <bristot@redhat.com>,
        Valentin Schneider <vschneid@redhat.com>
Cc:     linux-kernel@vger.kernel.org
Subject: [PATCH RESEND v4 0/2] sched: Queue task on wakelist in the same llc if the wakee cpu is idle
Date:   Thu,  9 Jun 2022 07:34:10 +0800
Message-Id: <20220608233412.327341-1-dtcccc@linux.alibaba.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Wakelist can help avoid cache bouncing and offload the overhead of waker
cpu. So far, using wakelist within the same llc only happens on
WF_ON_CPU, and this limitation could be removed to further improve
wakeup performance. The result of Unixbench Pipe-based Context Switching
can be improved up to ~10%.

The 1st patch introduces a more "correct" way to check whether the wakee
cpu is soon-to-be-idle.

The 2nd patch allows using wakelist in any case when the wakee cpu is
idle or soon-to-be-idle.

v4:
Add benchmark results about the 1st patch.
Modify some comments.

v3: https://lore.kernel.org/all/20220602040645.275555-1-dtcccc@linux.alibaba.com/
Add a patch to fix the check of nr_running.
After that, we can remove WF_ON_CPU to achieve the same purpose.
Thank Valentin and Mel.

v2: https://lore.kernel.org/all/20220527090544.527411-1-dtcccc@linux.alibaba.com/
Modify commit log to describe key point in detail.
Add more benchmark results on more archs.

v1: https://lore.kernel.org/all/20220513062427.2375743-1-dtcccc@linux.alibaba.com/

Tianchen Ding (2):
  sched: Fix the check of nr_running at queue wakelist
  sched: Remove the limitation of WF_ON_CPU on wakelist if wakee cpu is
    idle

 kernel/sched/core.c  | 30 ++++++++++++++++++------------
 kernel/sched/sched.h |  1 -
 2 files changed, 18 insertions(+), 13 deletions(-)

-- 
2.27.0