From: Peter Zijlstra <peterz@infradead.org>
To: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>,
perry.taylor@intel.com, caleb.biggers@intel.com,
kshipra.bopardikar@intel.com,
Kan Liang <kan.liang@linux.intel.com>,
Zhengjun Xing <zhengjun.xing@linux.intel.com>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
Maxime Coquelin <mcoquelin.stm32@gmail.com>,
Alexandre Torgue <alexandre.torgue@foss.st.com>,
James Clark <james.clark@arm.com>,
John Garry <john.garry@huawei.com>,
linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
Stephane Eranian <eranian@google.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH v2] perf metrics: Add literal for system TSC frequency
Date: Sat, 28 May 2022 16:01:57 +0200 [thread overview]
Message-ID: <YpIrVSGH314djkh9@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <76dce5d3-6c69-e403-c4d9-f882967a4467@linux.intel.com>
On Fri, May 27, 2022 at 07:54:19AM -0700, Andi Kleen wrote:
> > This all seems bonghits inspired... and perf actually does expose the
> > tsc frequency. What do you think is in perf_event_mmap_page::time_* ?
>
>
> That's not really available to perf stat, which is the primary metrics user.
Why not? You can mmap any perf-fd (even software events) and these
fields should be filled out.
It should work on any x86 CPU that has a TSC. The only caveat is that
the kernel must not have marked the TSC unstable.
It could even work for virt -- all you need is for virt to use
native_sched_clock() instead of the paravirt nonsense.
next prev parent reply other threads:[~2022-05-28 14:02 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-27 4:04 [PATCH v2] perf metrics: Add literal for system TSC frequency Ian Rogers
2022-05-27 9:49 ` Peter Zijlstra
2022-05-27 14:54 ` Andi Kleen
2022-05-27 15:57 ` Ian Rogers
2022-05-28 14:01 ` Peter Zijlstra [this message]
2022-05-28 14:50 ` Ian Rogers
2022-05-28 15:40 ` Peter Zijlstra
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