[PATCH] perf: implement --delay on perf trace

[Alexis Berlemont <alexis.berlemont@gmail.com>]

Signed-off-by: Alexis Berlemont <alexis.berlemont@gmail.com>
---
 tools/perf/builtin-trace.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index c298bd3..0bae454 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -2310,12 +2310,17 @@ static int trace__run(struct trace *trace, int argc, const char **argv)
 	if (err < 0)
 		goto out_error_mmap;
 
-	if (!target__none(&trace->opts.target))
+	if (!target__none(&trace->opts.target) && !trace->opts.initial_delay)
 		perf_evlist__enable(evlist);
 
 	if (forks)
 		perf_evlist__start_workload(evlist);
 
+	if (trace->opts.initial_delay) {
+		usleep(trace->opts.initial_delay * 1000);
+		perf_evlist__enable(evlist);
+	}
+
 	trace->multiple_threads = thread_map__pid(evlist->threads, 0) == -1 ||
 				  evlist->threads->nr > 1 ||
 				  perf_evlist__first(evlist)->attr.inherit;
@@ -2816,6 +2821,9 @@ int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
 		     "Default: kernel.perf_event_max_stack or " __stringify(PERF_MAX_STACK_DEPTH)),
 	OPT_UINTEGER(0, "proc-map-timeout", &trace.opts.proc_map_timeout,
 			"per thread proc mmap processing timeout in ms"),
+	OPT_UINTEGER('D', "delay", &trace.opts.initial_delay,
+		     "ms to wait before starting measurement after program "
+		     "start"),
 	OPT_END()
 	};
 	bool __maybe_unused max_stack_user_set = true;
-- 
2.10.0