Messages in this thread | ![/](/images/icornerl.gif) | | Date | Mon, 31 Aug 2020 11:11:23 +0200 | From | Jiri Olsa <> | Subject | Re: [PATCH v2 5/9] libperf: Add support for user space counter access |
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On Fri, Aug 28, 2020 at 02:56:10PM -0600, Rob Herring wrote:
SNIP
> #endif /* __LIBPERF_INTERNAL_MMAP_H */ > diff --git a/tools/lib/perf/include/perf/evsel.h b/tools/lib/perf/include/perf/evsel.h > index c82ec39a4ad0..6d0da962870c 100644 > --- a/tools/lib/perf/include/perf/evsel.h > +++ b/tools/lib/perf/include/perf/evsel.h > @@ -27,6 +27,7 @@ LIBPERF_API int perf_evsel__open(struct perf_evsel *evsel, struct perf_cpu_map * > struct perf_thread_map *threads); > LIBPERF_API void perf_evsel__close(struct perf_evsel *evsel); > LIBPERF_API void perf_evsel__close_cpu(struct perf_evsel *evsel, int cpu); > +LIBPERF_API void *perf_evsel__mmap(struct perf_evsel *evsel); > LIBPERF_API int perf_evsel__read(struct perf_evsel *evsel, int cpu, int thread, > struct perf_counts_values *count); > LIBPERF_API int perf_evsel__enable(struct perf_evsel *evsel); > diff --git a/tools/lib/perf/libperf.map b/tools/lib/perf/libperf.map > index 7be1af8a546c..733a0647be8b 100644 > --- a/tools/lib/perf/libperf.map > +++ b/tools/lib/perf/libperf.map > @@ -23,6 +23,7 @@ LIBPERF_0.0.1 { > perf_evsel__disable; > perf_evsel__open; > perf_evsel__close; > + perf_evsel__mmap; > perf_evsel__read; > perf_evsel__cpus; > perf_evsel__threads;
please put perf_evsel__mmap changes into separate patch
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
> +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
thanks, jirka
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