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From: Peter Zijlstra <peterz@infradead.org>
To: Namhyung Kim <namhyung@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Jiri Olsa <jolsa@redhat.com>, Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Stephane Eranian <eranian@google.com>,
	Andi Kleen <ak@linux.intel.com>, Ian Rogers <irogers@google.com>,
	Song Liu <songliubraving@fb.com>, Tejun Heo <tj@kernel.org>,
	kernel test robot <lkp@intel.com>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH v3 1/2] perf/core: Share an event with multiple cgroups
Date: Fri, 16 Apr 2021 15:39:35 +0200	[thread overview]
Message-ID: <YHmTl4bcjx6UA9Ko@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <CAM9d7chmLNTVrnKk3AEmLucR6Zi6Vd1ZESt9xNi2Q-vxudt32Q@mail.gmail.com>

On Fri, Apr 16, 2021 at 09:19:08PM +0900, Namhyung Kim wrote:
> > Are you actually using mmap() to read? I had a proposal for FORMAT_GROUP
> > like thing for mmap(), but I never implemented that (didn't get the
> > enthousiatic response I thought it would). But yeah, there's nowhere
> > near enough space in there for PERCPU.
> 
> Recently there's a patch to do it with rdpmc which needs to mmap first.
> 
> https://lore.kernel.org/lkml/20210414155412.3697605-1-robh@kernel.org/

Yeah, I'm not sure about that, I've not looked at it recently. The thing
is though; for RDPMC to work, you *NEED* to be on the same CPU as the
counter.

The typical RDPMC use-case is self monitoring.

  reply	other threads:[~2021-04-16 13:41 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-13 15:53 [PATCH v3 0/2] perf core: Sharing events with multiple cgroups Namhyung Kim
2021-04-13 15:53 ` [PATCH v3 1/2] perf/core: Share an event " Namhyung Kim
2021-04-15 14:51   ` Peter Zijlstra
2021-04-15 23:48     ` Namhyung Kim
2021-04-16  9:26       ` Peter Zijlstra
2021-04-16  9:29         ` Peter Zijlstra
2021-04-16 10:19           ` Namhyung Kim
2021-04-16 10:27           ` Peter Zijlstra
2021-04-16 11:22             ` Namhyung Kim
2021-04-16 11:59               ` Peter Zijlstra
2021-04-16 12:19                 ` Namhyung Kim
2021-04-16 13:39                   ` Peter Zijlstra [this message]
2021-05-09  7:13                 ` Namhyung Kim
2021-04-16 10:18         ` Namhyung Kim
2021-04-16  9:49     ` Namhyung Kim
2021-04-20 10:28       ` Peter Zijlstra
2021-04-20 18:37         ` Namhyung Kim
2021-04-20 18:43           ` Peter Zijlstra
2021-04-20  8:34     ` Stephane Eranian
2021-04-20  9:48       ` Peter Zijlstra
2021-04-20 11:28       ` Peter Zijlstra
2021-04-21 19:37         ` Namhyung Kim
2021-05-03 21:53           ` Namhyung Kim
2021-04-13 15:53 ` [PATCH v3 2/2] perf/core: Support reading group events with shared cgroups Namhyung Kim

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