diff options
author | Song Liu <songliubraving@fb.com> | 2019-03-11 22:30:50 -0700 |
---|---|---|
committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2019-03-21 11:27:03 -0300 |
commit | 657ee5531903339b06697581532ed32d4762526e (patch) | |
tree | 72cf6f621fd22b79d154168245eed807c0e12b83 /tools/perf/builtin-top.c | |
parent | 6987561c9e86eace45f2dbb0c564964a63f4150a (diff) | |
download | linux-657ee5531903339b06697581532ed32d4762526e.tar.bz2 |
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 <songliubraving@fb.com>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stanislav Fomichev <sdf@google.com>
Link: http://lkml.kernel.org/r/20190312053051.2690567-15-songliubraving@fb.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/builtin-top.c')
-rw-r--r-- | tools/perf/builtin-top.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c index c2ea22c4ea67..3ce8a8db6c1d 100644 --- a/tools/perf/builtin-top.c +++ b/tools/perf/builtin-top.c @@ -1501,6 +1501,7 @@ int cmd_top(int argc, const char **argv) "number of thread to run event synthesize"), OPT_END() }; + struct perf_evlist *sb_evlist = NULL; const char * const top_usage[] = { "perf top [<options>]", NULL @@ -1636,8 +1637,16 @@ int cmd_top(int argc, const char **argv) goto out_delete_evlist; } + if (perf_evlist__start_sb_thread(sb_evlist, target)) { + pr_debug("Couldn't start the BPF side band thread:\nBPF programs starting from now on won't be annotatable\n"); + opts->no_bpf_event = true; + } + status = __cmd_top(&top); + if (!opts->no_bpf_event) + perf_evlist__stop_sb_thread(sb_evlist); + out_delete_evlist: perf_evlist__delete(top.evlist); perf_session__delete(top.session); |