Commit-ID: fde54b7860ffff1c93e6b9abb3fbc3b8b95f2695
Gitweb: http://git.kernel.org/tip/fde54b7860ffff1c93e6b9abb3fbc3b8b95f2695
Author: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
AuthorDate: Mon, 11 Apr 2016 18:42:37 -0300
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Mon, 11 Apr 2016 22:18:23 -0300
perf trace: Make "--call-graph" affect just "raw_syscalls:sys_exit"
We don't need the callchains at the syscall enter tracepoint, just when
finishing it at syscall exit, so reduce the overhead by asking for
callchains just at syscall exit.
Suggested-by: Milian Wolff <milian.wolff@xxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-fja1ods5vqpg42mdz09xcz3r@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/builtin-trace.c | 22 +++++++++++++++++++++-
1 file changed, 21 insertions(+), 1 deletion(-)
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 08fb100..60ab7ce 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -2749,7 +2749,27 @@ static int trace__run(struct trace *trace, int argc, const char **argv)
goto out_delete_evlist;
}
- perf_evlist__config(evlist, &trace->opts, &callchain_param);
+ perf_evlist__config(evlist, &trace->opts, NULL);
+
+ if (trace->opts.callgraph_set && trace->syscalls.events.sys_exit) {
+ perf_evsel__config_callchain(trace->syscalls.events.sys_exit,
+ &trace->opts, &callchain_param);
+ /*
+ * Now we have evsels with different sample_ids, use
+ * PERF_SAMPLE_IDENTIFIER to map from sample to evsel
+ * from a fixed position in each ring buffer record.
+ *
+ * As of this the changeset introducing this comment, this
+ * isn't strictly needed, as the fields that can come before
+ * PERF_SAMPLE_ID are all used, but we'll probably disable
+ * some of those for things like copying the payload of
+ * pointer syscall arguments, and for vfs_getname we don't
+ * need PERF_SAMPLE_ADDR and PERF_SAMPLE_IP, so do this
+ * here as a warning we need to use PERF_SAMPLE_IDENTIFIER.
+ */
+ perf_evlist__set_sample_bit(evlist, IDENTIFIER);
+ perf_evlist__reset_sample_bit(evlist, ID);
+ }
signal(SIGCHLD, sig_handler);
signal(SIGINT, sig_handler);
--
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