From: Arnaldo Carvalho de Melo <[email protected]> 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 <[email protected]> Cc: Adrian Hunter <[email protected]> Cc: David Ahern <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Wang Nan <[email protected]> Link: http://lkml.kernel.org/n/[email protected] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]> --- 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 08fb100b91fa..60ab7ce3bc90 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); -- 2.5.5
