Re: [PATCHv3 00/10] libperf: Add sampling interface (leftover)

Arnaldo Carvalho de Melo
2019-10-18T18:29:38Z

Em Thu, Oct 17, 2019 at 12:59:08PM +0200, Jiri Olsa escreveu:
> hi,
> sending changes for exporting basic sampling interface
> in libperf. It's now possible to use following code in
> applications via libperf:

Thanks, applied.

- Arnaldo
> --- (example is without error checks for simplicity)
>
> struct perf_event_attr attr = {
> .type = PERF_TYPE_TRACEPOINT,
> .sample_period = 1,
> .wakeup_watermark = 1,
> .disabled = 1,
> };
> /* ... setup attr */
>
> cpus = perf_cpu_map__new(NULL);
>
> evlist = perf_evlist__new();
> evsel = perf_evsel__new(&attr);
> perf_evlist__add(evlist, evsel);
>
> perf_evlist__set_maps(evlist, cpus, NULL);
>
> err = perf_evlist__open(evlist);
> err = perf_evlist__mmap(evlist, 4);
>
> err = perf_evlist__enable(evlist);
>
> /* ... monitored area, plus all the other cpus */
>
> err = perf_evlist__disable(evlist);
>
> perf_evlist__for_each_mmap(evlist, map) {
> if (perf_mmap__read_init(map) < 0)
> continue;
>
> while ((event = perf_mmap__read_event(map)) != NULL) {
> perf_mmap__consume(map);
> }
>
> perf_mmap__read_done(map);
> }
>
> perf_evlist__delete(evlist);
> perf_cpu_map__put(cpus);
>
> --- (end)
>
> Nothing is carved in stone so far, the interface is exported
> as is available in perf now and we can change it as we want.
>
> New tests are added in test-evlist.c to do thread and cpu based
> sampling.
>
> All the functionality should not change, however there's considerable
> mmap code rewrite.
>
> Now we have perf_evlist__mmap_ops called by both perf and libperf
> mmaps functions with specific 'struct perf_evlist_mmap_ops'
> callbacks:
>
> - get - to get mmap object, both libperf and perf use different
> objects, because perf needs to carry more data for aio,
> compression and auxtrace
> - mmap - to actually mmap the object, it's simple mmap for libperf,
> but more work for perf wrt aio, compression and auxtrace
> - idx - callback to get current IDs, used only in perf for auxtrace
> setup
>
>
> It would be great if guys could run your usual workloads to see if all
> is fine.. so far so good in my tests ;-)
>
>
> It's also available in here:
> git://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git
> perf/lib
>
> v3 changes:
> - changed mmap0 and mmap_ovw0 to mmap_first and mmap_ovw_first
> - rebased to latest perf/core
> - portion of patches already taken
>
> v2 changes:
> - rebased to latest perf/core
> - portion of patches already taken
> - explained mmap refcnt management in following patch changelog:
> libperf: Centralize map refcnt setting
>
> thanks,
> jirka
>
>
> Cc: Kan Liang <kan.liang@linux.intel.com>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Cc: Adrian Hunter <adrian.hunter@intel.com>
> Cc: Ian Rogers <irogers@google.com>
> Cc: Stephane Eranian <eranian@google.com>
> Cc: Song Liu <songliubraving@fb.com>
> Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
> Cc: Andi Kleen <ak@linux.intel.com>
> ---
> Jiri Olsa (10):
> libperf: Add perf_evlist__for_each_mmap function
> libperf: Move mmap allocation to perf_evlist__mmap_ops::get
> libperf: Move mask setup to perf_evlist__mmap_ops function
> libperf: Link static tests with libapi.a
> libperf: Add _GNU_SOURCE define to compilation
> libperf: Add tests_mmap_thread test
> libperf: Add tests_mmap_cpus test
> libperf: Keep count of failed tests
> libperf: Do not export perf_evsel__init/perf_evlist__init
> libperf: Add pr_err macro
>
> tools/perf/lib/Makefile | 2 ++
> tools/perf/lib/evlist.c | 71 ++++++++++++++++++++++++++++++++++++++---------------
> tools/perf/lib/include/internal/evlist.h | 3 +++
> tools/perf/lib/include/internal/evsel.h | 1 +
> tools/perf/lib/include/internal/mmap.h | 5 ++--
> tools/perf/lib/include/internal/tests.h | 20 ++++++++++++---
> tools/perf/lib/include/perf/core.h | 1 +
> tools/perf/lib/include/perf/evlist.h | 10 +++++++-
> tools/perf/lib/include/perf/evsel.h | 2 --
> tools/perf/lib/internal.h | 3 +++
> tools/perf/lib/libperf.map | 3 +--
> tools/perf/lib/mmap.c | 6 +++--
> tools/perf/lib/tests/Makefile | 8 +++---
> tools/perf/lib/tests/test-cpumap.c | 2 +-
> tools/perf/lib/tests/test-evlist.c | 218 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
> tools/perf/lib/tests/test-evsel.c | 2 +-
> tools/perf/lib/tests/test-threadmap.c | 2 +-
> tools/perf/util/evlist.c | 29 +++++++++-------------
> 18 files changed, 333 insertions(+), 55 deletions(-)

--

- Arnaldo