From: Andi Kleen <ak@linux.intel.com>
To: Vince Weaver <vincent.weaver@maine.edu>
Cc: Peter Zijlstra <peterz@infradead.org>,
"Liang, Kan" <kan.liang@linux.intel.com>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Namhyung Kim <namhyung@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@kernel.org>,
Adrian Hunter <adrian.hunter@intel.com>,
linux-kernel@vger.kernel.org, mathieu.desnoyers@efficios.com
Subject: Re: perf: is it possible to userspace rdpmc but only on a certain core type
Date: Thu, 23 Jan 2025 21:18:53 -0800 [thread overview]
Message-ID: <Z5MivTsyHedobQGY@tassilo> (raw)
In-Reply-To: <a55139ec-b46d-0854-4d75-845f3b4f788b@maine.edu>
On Thu, Jan 23, 2025 at 02:45:33PM -0500, Vince Weaver wrote:
> On Thu, 23 Jan 2025, Andi Kleen wrote:
>
> > > I have a student working on this for PAPI. If we get it working we can
> > > see if perf could use support too if it doesn't have it already.
> >
> > perf user space doesn't have a ring 3 self access library.
>
> what happens if you're doing top-down measurments with perf on a hybrid
> system and perf gets migrated to an E-core?
>
> or are you saying perf always uses a syscall to read the top-down values
> and doesn't use rdpmc in that case?
perf always uses system calls or mmap.
-Andi
prev parent reply other threads:[~2025-01-24 5:18 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-17 22:04 perf: is it possible to userspace rdpmc but only on a certain core type Vince Weaver
2025-01-20 16:44 ` Liang, Kan
2025-01-21 12:52 ` Peter Zijlstra
2025-01-21 14:30 ` Mathieu Desnoyers
2025-01-22 21:51 ` Vince Weaver
2025-01-23 18:14 ` Andi Kleen
2025-01-23 19:45 ` Vince Weaver
2025-01-24 5:18 ` Andi Kleen [this message]
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