From 657ee5531903339b06697581532ed32d4762526e Mon Sep 17 00:00:00 2001 From: Song Liu Date: Mon, 11 Mar 2019 22:30:50 -0700 Subject: perf evlist: Introduce side band thread This patch introduces side band thread that captures extended information for events like PERF_RECORD_BPF_EVENT. This new thread uses its own evlist that uses ring buffer with very low watermark for lower latency. To use side band thread, we need to: 1. add side band event(s) by calling perf_evlist__add_sb_event(); 2. calls perf_evlist__start_sb_thread(); 3. at the end of perf run, perf_evlist__stop_sb_thread(). In the next patch, we use this thread to handle PERF_RECORD_BPF_EVENT. Committer notes: Add fix by Jiri Olsa for when te sb_tread can't get started and then at the end the stop_sb_thread() segfaults when joining the (non-existing) thread. That can happen when running 'perf top' or 'perf record' as a normal user, for instance. Further checks need to be done on top of this to more graciously handle these possible failure scenarios. Signed-off-by: Song Liu Reviewed-by: Jiri Olsa Tested-by: Arnaldo Carvalho de Melo Cc: Alexei Starovoitov Cc: Daniel Borkmann Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Stanislav Fomichev Link: http://lkml.kernel.org/r/20190312053051.2690567-15-songliubraving@fb.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/evsel.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'tools/perf/util/evsel.h') diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h index cc578e02e08f..0f2c6c93d721 100644 --- a/tools/perf/util/evsel.h +++ b/tools/perf/util/evsel.h @@ -73,6 +73,8 @@ struct perf_evsel_config_term { struct perf_stat_evsel; +typedef int (perf_evsel__sb_cb_t)(union perf_event *event, void *data); + /** struct perf_evsel - event selector * * @evlist - evlist this evsel is in, if it is in one. @@ -151,6 +153,10 @@ struct perf_evsel { bool collect_stat; bool weak_group; const char *pmu_name; + struct { + perf_evsel__sb_cb_t *cb; + void *data; + } side_band; }; union u64_swap { -- cgit v1.2.3