trace2: add absolute elapsed time to start event

Add elapsed process time to "start" event to measure
the performance of early process startup.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/trace2.c b/trace2.c
index 6dd51e6aa5..1c180062dd 100644
--- a/trace2.c
+++ b/trace2.c
@@ -182,13 +182,19 @@ void trace2_cmd_start_fl(const char *file, int line, const char **argv)
 {
 	struct tr2_tgt *tgt_j;
 	int j;
+	uint64_t us_now;
+	uint64_t us_elapsed_absolute;
 
 	if (!trace2_enabled)
 		return;
 
+	us_now = getnanotime() / 1000;
+	us_elapsed_absolute = tr2tls_absolute_elapsed(us_now);
+
 	for_each_wanted_builtin (j, tgt_j)
 		if (tgt_j->pfn_start_fl)
-			tgt_j->pfn_start_fl(file, line, argv);
+			tgt_j->pfn_start_fl(file, line, us_elapsed_absolute,
+					    argv);
 }
 
 int trace2_cmd_exit_fl(const char *file, int line, int code)