From: Tejun Heo <tj@kernel.org>
To: Andrea Righi <arighi@nvidia.com>
Cc: David Vernet <void@manifault.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] sched_ext: Introduce LLC awareness to the default idle selection policy
Date: Tue, 22 Oct 2024 09:11:52 -1000 [thread overview]
Message-ID: <Zxf4-DewpSO8Lcsg@slm.duckdns.org> (raw)
In-Reply-To: <Zxe89zvC5uhI7ZxG@gpd3>
Hello,
On Tue, Oct 22, 2024 at 04:55:51PM +0200, Andrea Righi wrote:
...
> Thinking more about this, we can avoid re-generating the llc_cpus
> cpumask when the task can run on all CPUs (likely the majority of the
> cases) and it's probably more efficient to check for
> cpumask_equal(p->cpus_ptr, cpu_possible_mask) and just use llc_mask in
> this case.
At the simplest, we can just skip llc-aware idle picking if not all CPUs are
allowed. Also, it's probably cheaper to test p->nr_cpus_allowed than testing
cpus_ptr.
> We could also optimize tasks that can only run on 1 CPU, but we never
> call ops.select_cpu() for them, they're just skipped in
> select_task_rq(), so I'm not sure if we should handle this special case
> (maybe I can add a comment, to make it more clear).
Yeah, a comment can be helpful.
Thanks.
--
tejun
next prev parent reply other threads:[~2024-10-22 19:11 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-22 10:14 [PATCH v2] sched_ext: Introduce LLC awareness to the default idle selection policy Andrea Righi
2024-10-22 14:55 ` Andrea Righi
2024-10-22 19:11 ` Tejun Heo [this message]
2024-10-22 21:33 ` Andrea Righi
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