From: Shubhang Kaushik Prasanna Kumar <shkaushik@amperecomputing.com>
To: "vineethr@linux.ibm.com" <vineethr@linux.ibm.com>
Cc: Shijie Huang <Shijie.Huang@amperecomputing.com>,
Adam Li <adam.li@amperecomputing.com>,
"bsegall@google.com" <bsegall@google.com>,
"cl@gentwo.org" <cl@gentwo.org>,
"dietmar.eggemann@arm.com" <dietmar.eggemann@arm.com>,
"juri.lelli@redhat.com" <juri.lelli@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"mgorman@suse.de" <mgorman@suse.de>,
"mingo@redhat.com" <mingo@redhat.com>,
"peterz@infradead.org" <peterz@infradead.org>,
"rostedt@goodmis.org" <rostedt@goodmis.org>,
"sh@gentwo.org" <sh@gentwo.org>,
Shubhang Kaushik OS <shubhang@os.amperecomputing.com>,
"vincent.guittot@linaro.org" <vincent.guittot@linaro.org>,
"vschneid@redhat.com" <vschneid@redhat.com>,
Frank Wang <zwang@amperecomputing.com>
Subject: Re: [PATCH v2] sched/fair: Prefer cache locality for EAS wakeup
Date: Thu, 13 Nov 2025 00:03:33 +0000 [thread overview]
Message-ID: <548ADCD4-7726-460C-A645-8BF74ADBCB06@os.amperecomputing.com> (raw)
Hi Vineeth,
> Is cache locality prioritized even over idle CPU availability?
I had assumed that the fast path prioritizes cache locality over idle CPU selection. However, our performance measurements indicate that, in this specific scenario, the trade-off is not worthwhile.
The data shows that prioritizing the busy, `cache-hot` core leads to performance regressions and an overload on wakeup. Which means an overhead of staying on the busy core outweighs the cost of migrating to an idle core.
In development, I am trying an alternative approach to benefit from cache locality in this path.
Regards,
Shubhang Kaushik
next reply other threads:[~2025-11-13 0:03 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-13 0:03 Shubhang Kaushik Prasanna Kumar [this message]
-- strict thread matches above, loose matches on Subject: below --
2025-10-30 19:19 Shubhang Kaushik via B4 Relay
2025-10-31 10:17 ` Christian Loehle
2025-10-31 16:59 ` Shubhang Kaushik OS
2025-10-31 18:11 ` Christian Loehle
2025-11-02 10:06 ` Christian Loehle
2025-11-02 7:12 ` Madadi Vineeth Reddy
2025-11-03 9:04 ` Vincent Guittot
2025-11-13 0:26 ` Shubhang Kaushik OS
2025-11-13 14:54 ` Dietmar Eggemann
2025-11-14 18:27 ` Shubhang Kaushik OS
2025-11-14 13:36 ` Vincent Guittot
2025-11-18 1:27 ` Shubhang Kaushik OS
2025-11-20 14:37 ` Vincent Guittot
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