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From: Dietmar Eggemann <dietmar.eggemann@arm.com>
To: Shubhang <sh@gentwo.org>,
	shubhang@os.amperecomputing.com, Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Juri Lelli <juri.lelli@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
	Valentin Schneider <vschneid@redhat.com>,
	Shijie Huang <Shijie.Huang@amperecomputing.com>,
	Frank Wang <zwang@amperecomputing.com>
Cc: Christopher Lameter <cl@gentwo.org>,
	Adam Li <adam.li@amperecomputing.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] sched/fair: Prefer cache-hot prev_cpu for wakeup
Date: Fri, 31 Oct 2025 12:32:13 +0100	[thread overview]
Message-ID: <b8cb522a-83be-49ec-a4ca-5c084757fb67@arm.com> (raw)
In-Reply-To: <d1cbc53d-d4cf-bc5a-6468-89e9a1d86f33@gentwo.org>

On 30.10.25 17:35, Shubhang wrote:
> The system is an 80 core Ampere Altra with a two-level
> sched domain topology. The MC domain contains all 80 cores.

Ah OK. So I assume the other SD is CLS with 2 CPUs?

Does this mean you guys have recently changed the sched topology on this
thing? I still remember setups with 2 CPUs in MC and 80 CPUs on PKG.

If this is the case, is:

db1e59483dfd - topology: make core_mask include at least
cluster_siblings (2022-04-20 Darren Hart)

still needed in this case?

> I agree that placing the condition earlier in `select_idle_sibling()`>
aligns better with convention. I will move the check (EAS Aware) to the
> top of the function and submit a v2 patch.
I can't imagine that you run EAS on this machine? It needs heterogeneous
CPUs which you shouldn't have. Looks like that Christian L. was asking
you already on your v2.

[...]

  reply	other threads:[~2025-10-31 11:32 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-10-17 23:00 [PATCH] sched/fair: Prefer cache-hot prev_cpu for wakeup Shubhang Kaushik via B4 Relay
2025-10-20 12:36 ` Phil Auld
2025-10-22 16:45   ` Shubhang Kaushik OS
2025-10-22 16:54 ` Vincent Guittot
2025-10-28  7:29 ` kernel test robot
2025-10-29  4:17 ` kernel test robot
2025-10-30 10:14 ` Dietmar Eggemann
2025-10-30 16:35   ` Shubhang
2025-10-31 11:32     ` Dietmar Eggemann [this message]
2025-10-31 16:45       ` Shubhang Kaushik OS

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