From: Rob Herring <robh@kernel.org>
To: Jiri Olsa <jolsa@redhat.com>
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>, Will Deacon <will@kernel.org>,
"moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v2 5/9] libperf: Add support for user space counter access
Date: Wed, 2 Sep 2020 10:58:34 -0600 [thread overview]
Message-ID: <CAL_Jsq+rrQWObtaTQpoxjJbFJeWPf5VxnOZyp6pZzZcb3Ybv+w@mail.gmail.com> (raw)
In-Reply-To: <20200831091123.GB406859@krava>
On Mon, Aug 31, 2020 at 3:11 AM Jiri Olsa <jolsa@redhat.com> wrote:
>
> On Fri, Aug 28, 2020 at 02:56:10PM -0600, Rob Herring wrote:
>
> SNIP
> > +int perf_mmap__read_self(struct perf_mmap *map, struct perf_counts_values *count)
> > +{
> > + struct perf_event_mmap_page *pc = map->base;
> > + u32 seq, idx, time_mult = 0, time_shift = 0;
> > + u64 cnt, cyc = 0, time_offset = 0, time_cycles = 0, time_mask = ~0ULL;
> > +
> > + BUG_ON(!pc);
> > +
> > + if (!pc->cap_user_rdpmc)
> > + return -1;
> > +
> > + do {
> > + seq = READ_ONCE(pc->lock);
> > + barrier();
> > +
> > + count->ena = READ_ONCE(pc->time_enabled);
> > + count->run = READ_ONCE(pc->time_running);
> > +
> > + if (pc->cap_user_time && count->ena != count->run) {
> > + cyc = read_timestamp();
> > + time_mult = READ_ONCE(pc->time_mult);
> > + time_shift = READ_ONCE(pc->time_shift);
> > + time_offset = READ_ONCE(pc->time_offset);
> > +
> > + if (pc->cap_user_time_short) {
> > + time_cycles = READ_ONCE(pc->time_cycles);
> > + time_mask = READ_ONCE(pc->time_mask);
> > + }
> > + }
> > +
> > + idx = READ_ONCE(pc->index);
> > + cnt = READ_ONCE(pc->offset);
> > + if (pc->cap_user_rdpmc && idx) {
>
> no need to check pc->cap_user_rdpmc again
I was thinking cap_user_rdpmc could change, but I guess idx will
always be 0 in that case.
> > +static int test_stat_user_read(int event)
> > +{
> > + struct perf_counts_values counts = { .val = 0 };
> > + struct perf_thread_map *threads;
> > + struct perf_evsel *evsel;
> > + struct perf_event_mmap_page *pc;
> > + struct perf_event_attr attr = {
> > + .type = PERF_TYPE_HARDWARE,
> > + .config = event,
> > + };
> > + int err, i;
> > +
> > + threads = perf_thread_map__new_dummy();
> > + __T("failed to create threads", threads);
> > +
> > + perf_thread_map__set_pid(threads, 0, 0);
> > +
> > + evsel = perf_evsel__new(&attr);
> > + __T("failed to create evsel", evsel);
> > +
> > + err = perf_evsel__open(evsel, NULL, threads);
> > + __T("failed to open evsel", err == 0);
> > +
> > + pc = perf_evsel__mmap(evsel);
> > + __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
> > +
> > + perf_evsel__read(evsel, 0, 0, &counts);
> > + __T("failed to read value for evsel", counts.val != 0);
> > +
> > + fputs("\n", stderr);
> > + for (i = 0; i < 5; i++) {
> > + volatile int count = 0x10000 << i;
> > + __u64 start, end, last = 0;
> > +
> > + fprintf(stderr, "\tloop = %u, ", count);
>
> we should add support to display verbose output for tests,
> because right now this breaks the output:
>
> - running test-cpumap.c...OK
> - running test-threadmap.c...OK
> - running test-evlist.c...OK
> - running test-evsel.c...
> loop = 65536, count = 328035
> loop = 131072, count = 655715
> loop = 262144, count = 1311075
> loop = 524288, count = 2627060
> loop = 1048576, count = 5253540
>
> loop = 65536, count = 327594
> loop = 131072, count = 659930
> loop = 262144, count = 1378892
> loop = 524288, count = 2664341
> loop = 1048576, count = 5365682
> OK
>
> but we can do it in separate change later
Would you like me to just comment this out then for now?
Rob
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next prev parent reply other threads:[~2020-09-02 17:00 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-28 20:56 [PATCH v2 0/9] libperf and arm64 userspace counter access support Rob Herring
2020-08-28 20:56 ` [PATCH v2 1/9] arm64: pmu: Add hook to handle pmu-related undefined instructions Rob Herring
2020-08-28 20:56 ` [PATCH v2 2/9] arm64: pmu: Add function implementation to update event index in userpage Rob Herring
2020-08-28 20:56 ` [PATCH v2 3/9] arm64: perf: Enable pmu counter direct access for perf event on armv8 Rob Herring
2020-08-28 20:56 ` [PATCH v2 4/9] tools/include: Add an initial math64.h Rob Herring
2020-08-28 20:56 ` [PATCH v2 5/9] libperf: Add support for user space counter access Rob Herring
2020-08-31 9:11 ` Jiri Olsa
2020-09-02 16:58 ` Rob Herring [this message]
2020-08-31 9:11 ` Jiri Olsa
2020-09-02 17:01 ` Rob Herring
2020-09-02 18:07 ` Ian Rogers
2020-09-02 19:48 ` Rob Herring
2020-09-04 5:51 ` Ian Rogers
2020-08-28 20:56 ` [PATCH v2 6/9] libperf: Add arm64 support to perf_mmap__read_self() Rob Herring
2020-08-28 20:56 ` [PATCH v2 7/9] perf: arm64: Add test for userspace counter access on heterogeneous systems Rob Herring
2020-08-28 20:56 ` [PATCH v2 8/9] Documentation: arm64: Document PMU counters access from userspace Rob Herring
2020-08-28 20:56 ` [PATCH v2 9/9] perf: Remove x86 specific rdpmc test Rob Herring
2020-08-31 9:11 ` Jiri Olsa
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