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From:   Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Date:   Fri, 18 Oct 2019 15:29:31 -0300
To:     Jiri Olsa <jolsa@kernel.org>
Cc:     Kan Liang <kan.liang@linux.intel.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Ian Rogers <irogers@google.com>,
        Stephane Eranian <eranian@google.com>,
        Song Liu <songliubraving@fb.com>,
        Alexey Budankov <alexey.budankov@linux.intel.com>,
        Andi Kleen <ak@linux.intel.com>,
        lkml <linux-kernel@vger.kernel.org>,
        Ingo Molnar <mingo@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Michael Petlan <mpetlan@redhat.com>,
        Jin Yao <yao.jin@linux.intel.com>
Subject: Re: [PATCHv3 00/10] libperf: Add sampling interface (leftover)
Message-ID: <20191018182931.GG1797@kernel.org>
References: <20191017105918.20873-1-jolsa@kernel.org>
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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