From: Peter Zijlstra <peterz@infradead.org>
To: Namhyung Kim <namhyung@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Stephane Eranian <eranian@google.com>,
Kan Liang <kan.liang@linux.intel.com>,
Ravi Bangoria <ravi.bangoria@amd.com>,
stable@vger.kernel.org
Subject: Re: [PATCH] perf/core: Introduce cpuctx->cgrp_ctx_list
Date: Wed, 4 Oct 2023 18:02:24 +0200 [thread overview]
Message-ID: <20231004160224.GB6307@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <20231004040844.797044-1-namhyung@kernel.org>
On Tue, Oct 03, 2023 at 09:08:44PM -0700, Namhyung Kim wrote:
> But after the change, it ended up iterating all pmus/events in the cpu
> context if there's a cgroup event somewhere on the cpu context.
> Unfortunately it includes uncore pmus which have much longer latency to
> control.
Can you describe the problem in more detail please?
We have cgrp as part of the tree key: {cpu, pmu, cgroup, idx},
so it should be possible to find a specific cgroup for a cpu and or skip
to the next cgroup on that cpu in O(log n) time.
> To fix the issue, I restored a linked list equivalent to cgrp_cpuctx_list
> in the perf_cpu_context and link perf_cpu_pmu_contexts that have cgroup
> events only. Also add new helpers to enable/disable and does ctx sched
> in/out for cgroups.
Adding a list and duplicating the whole scheduling infrastructure seems
'unfortunate' at best.
next prev parent reply other threads:[~2023-10-04 16:02 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-04 4:08 [PATCH] perf/core: Introduce cpuctx->cgrp_ctx_list Namhyung Kim
2023-10-04 7:26 ` Ingo Molnar
2023-10-04 15:01 ` Namhyung Kim
2023-10-04 15:42 ` Ingo Molnar
2023-10-04 21:27 ` Namhyung Kim
2023-10-04 16:02 ` Peter Zijlstra [this message]
2023-10-04 16:32 ` Namhyung Kim
2023-10-09 21:04 ` Peter Zijlstra
2023-10-10 4:57 ` Namhyung Kim
2023-10-11 3:45 ` Namhyung Kim
2023-10-11 7:51 ` Peter Zijlstra
2023-10-11 9:50 ` Peter Zijlstra
2023-10-11 16:02 ` Namhyung Kim
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