From: Tejun Heo <tj@kernel.org>
To: Andrea Righi <arighi@nvidia.com>
Cc: David Vernet <void@manifault.com>,
Changwoo Min <changwoo@igalia.com>,
bpf@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/8] sched_ext: idle: Extend topology optimizations to all tasks
Date: Fri, 14 Mar 2025 08:21:49 -1000 [thread overview]
Message-ID: <Z9RzvWMiHWqiO2v7@slm.duckdns.org> (raw)
In-Reply-To: <20250314094827.167563-4-arighi@nvidia.com>
Hello,
On Fri, Mar 14, 2025 at 10:45:35AM +0100, Andrea Righi wrote:
...
> - if (p->nr_cpus_allowed >= num_possible_cpus()) {
> - if (static_branch_maybe(CONFIG_NUMA, &scx_selcpu_topo_numa))
> - numa_cpus = numa_span(prev_cpu);
> -
> - if (static_branch_maybe(CONFIG_SCHED_MC, &scx_selcpu_topo_llc))
> - llc_cpus = llc_span(prev_cpu);
> + if (static_branch_maybe(CONFIG_NUMA, &scx_selcpu_topo_numa)) {
> + struct cpumask *cpus = numa_span(prev_cpu);
> +
> + if (cpus && !cpumask_equal(cpus, p->cpus_ptr)) {
> + if (cpumask_subset(cpus, p->cpus_ptr)) {
> + numa_cpus = cpus;
> + } else {
> + numa_cpus = this_cpu_cpumask_var_ptr(local_numa_idle_cpumask);
> + if (!cpumask_and(numa_cpus, cpus, p->cpus_ptr))
> + numa_cpus = NULL;
> + }
> + }
> + }
> + if (static_branch_maybe(CONFIG_SCHED_MC, &scx_selcpu_topo_llc)) {
> + struct cpumask *cpus = llc_span(prev_cpu);
> +
> + if (cpus && !cpumask_equal(cpus, p->cpus_ptr)) {
> + if (cpumask_subset(cpus, p->cpus_ptr)) {
> + llc_cpus = cpus;
> + } else {
> + llc_cpus = this_cpu_cpumask_var_ptr(local_llc_idle_cpumask);
> + if (!cpumask_and(llc_cpus, cpus, p->cpus_ptr))
> + llc_cpus = NULL;
> + }
> + }
>
Wouldn't it still make sense to special case p->nr_cpus_allowed >=
num_possible_cpus()? That'd be vast majority of cases and we can skip all
the cpumask comparisons for them.
Thanks.
--
tejun
next prev parent reply other threads:[~2025-03-14 18:21 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-14 9:45 [PATCHSET v3 sched_ext/for-6.15] sched_ext: Enhance built-in idle selection with allowed CPUs Andrea Righi
2025-03-14 9:45 ` [PATCH 1/8] sched_ext: idle: Honor idle flags in the built-in idle selection policy Andrea Righi
2025-03-14 9:45 ` [PATCH 2/8] sched_ext: idle: Refactor scx_select_cpu_dfl() Andrea Righi
2025-03-14 18:17 ` Tejun Heo
2025-03-14 9:45 ` [PATCH 3/8] sched_ext: idle: Extend topology optimizations to all tasks Andrea Righi
2025-03-14 18:21 ` Tejun Heo [this message]
2025-03-14 20:05 ` Andrea Righi
2025-03-14 9:45 ` [PATCH 4/8] sched_ext: idle: Explicitly pass allowed cpumask to scx_select_cpu_dfl() Andrea Righi
2025-03-14 9:45 ` [PATCH 5/8] sched_ext: idle: Accept an arbitrary cpumask in scx_select_cpu_dfl() Andrea Righi
2025-03-14 9:45 ` [PATCH 6/8] sched_ext: idle: Introduce scx_bpf_select_cpu_and() Andrea Righi
2025-03-15 1:35 ` Changwoo Min
2025-03-15 9:08 ` Andrea Righi
2025-03-14 9:45 ` [PATCH 7/8] selftests/sched_ext: Add test for scx_bpf_select_cpu_and() Andrea Righi
2025-03-14 9:45 ` [PATCH 8/8] sched_ext: idle: Deprecate scx_bpf_select_cpu_dfl() Andrea Righi
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