From: Jiri Olsa <jolsa@redhat.com>
To: Rob Herring <robh@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
Ian Rogers <irogers@google.com>,
Peter Zijlstra <peterz@infradead.org>,
Catalin Marinas <catalin.marinas@arm.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Raphael Gault <raphael.gault@arm.com>,
Ingo Molnar <mingo@redhat.com>,
Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>,
Jonathan Cameron <Jonathan.Cameron@huawei.com>,
Namhyung Kim <namhyung@kernel.org>,
Itaru Kitayama <itaru.kitayama@gmail.com>,
Will Deacon <will@kernel.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v4 4/9] libperf: Add libperf_evsel__mmap()
Date: Thu, 5 Nov 2020 23:41:21 +0100 [thread overview]
Message-ID: <20201105224121.GA4112111@krava> (raw)
In-Reply-To: <CAL_JsqJd1W_n1vGYmUP+Azcv__pCT+UU+VLPqLy2aJDwajZzCg@mail.gmail.com>
On Thu, Nov 05, 2020 at 10:19:24AM -0600, Rob Herring wrote:
SNIP
> > > >
> > > > that maps page for each event, then perf_evsel__read
> > > > could go through the fast code, no?
> > >
> > > No, because we're not self-monitoring (pid == 0 and cpu == -1). With
> > > the following change:
> > >
> > > diff --git a/tools/lib/perf/tests/test-evsel.c
> > > b/tools/lib/perf/tests/test-evsel.c
> > > index eeca8203d73d..1fca9c121f7c 100644
> > > --- a/tools/lib/perf/tests/test-evsel.c
> > > +++ b/tools/lib/perf/tests/test-evsel.c
> > > @@ -17,6 +17,7 @@ static int test_stat_cpu(void)
> > > {
> > > struct perf_cpu_map *cpus;
> > > struct perf_evsel *evsel;
> > > + struct perf_event_mmap_page *pc;
> > > struct perf_event_attr attr = {
> > > .type = PERF_TYPE_SOFTWARE,
> > > .config = PERF_COUNT_SW_CPU_CLOCK,
> > > @@ -32,6 +33,15 @@ static int test_stat_cpu(void)
> > > err = perf_evsel__open(evsel, cpus, NULL);
> > > __T("failed to open evsel", err == 0);
> > >
> > > + pc = perf_evsel__mmap(evsel, 0);
> > > + __T("failed to mmap evsel", pc);
> > > +
> > > +#if defined(__i386__) || defined(__x86_64__) || defined(__aarch64__)
> > > + __T("userspace counter access not supported", pc->cap_user_rdpmc);
> > > + __T("userspace counter access not enabled", pc->index);
> > > + __T("userspace counter width not set", pc->pmc_width >= 32);
> > > +#endif
> >
> > I'll need to check, I'm surprised this would depend on the way
> > you open the event
>
> Any more thoughts on this?
sry I got stuck with other stuff.. I tried your change
and pc->cap_user_rdpmc is 0 because the test creates
software event, which does not support that
when I change that to:
.type = PERF_TYPE_HARDWARE,
.config = PERF_COUNT_HW_CPU_CYCLES,
I don't see any of those warning you added
jirka
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next prev parent reply other threads:[~2020-11-05 22:42 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-01 14:01 [PATCH v4 0/9] libperf and arm64 userspace counter access support Rob Herring
2020-10-01 14:01 ` [PATCH v4 1/9] arm64: pmu: Add function implementation to update event index in userpage Rob Herring
2020-10-01 14:01 ` [PATCH v4 2/9] arm64: perf: Enable pmu counter direct access for perf event on armv8 Rob Herring
2020-11-13 18:06 ` Mark Rutland
2020-11-19 18:35 ` Rob Herring
2020-11-19 19:15 ` Will Deacon
2020-11-20 20:03 ` Rob Herring
2020-11-20 22:08 ` Rob Herring
2020-12-02 14:57 ` Rob Herring
2021-01-07 0:17 ` Rob Herring
2020-10-01 14:01 ` [PATCH v4 3/9] tools/include: Add an initial math64.h Rob Herring
2020-10-01 14:01 ` [PATCH v4 4/9] libperf: Add libperf_evsel__mmap() Rob Herring
2020-10-14 11:05 ` Jiri Olsa
2020-10-16 21:39 ` Rob Herring
2020-10-19 20:15 ` Jiri Olsa
2020-10-20 14:38 ` Rob Herring
2020-10-20 15:35 ` Jiri Olsa
2020-10-20 17:11 ` Rob Herring
2020-10-21 11:24 ` Jiri Olsa
2020-11-05 16:19 ` Rob Herring
2020-11-05 22:41 ` Jiri Olsa [this message]
2020-11-06 21:56 ` Rob Herring
2020-11-11 12:00 ` Jiri Olsa
2020-11-11 14:50 ` Rob Herring
2020-10-01 14:01 ` [PATCH v4 5/9] libperf: tests: Add support for verbose printing Rob Herring
2020-10-01 14:01 ` [PATCH v4 6/9] libperf: Add support for user space counter access Rob Herring
2020-10-01 14:01 ` [PATCH v4 7/9] libperf: Add arm64 support to perf_mmap__read_self() Rob Herring
2020-10-01 14:01 ` [PATCH v4 8/9] perf: arm64: Add test for userspace counter access on heterogeneous systems Rob Herring
2020-10-01 14:01 ` [PATCH v4 9/9] Documentation: arm64: Document PMU counters access from userspace Rob Herring
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