From: Willy Tarreau <w@1wt.eu>
Date: Tue, 19 Nov 2024 15:42:40 +0000 (+0100)
Subject: MINOR: stream: don't update s->lat_time when the wakeup date is not set
X-Git-Tag: v3.1-dev14~71
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=33c461314c7dbd24565fcc0c0a795fc779618bf3;p=thirdparty%2Fhaproxy.git

MINOR: stream: don't update s->lat_time when the wakeup date is not set

In 2.7 was added a stream wakeup latency calculation with commit
6a28a30efa ("MINOR: tasks: do not keep cpu and latency times in struct
task"). However, due to the transformation of the previous code, it
kept unconditionally updating s->lat_time even of the sched_wake_date
was zero. In other words, s->lat_time is constantly updated for the
huge majority of calls that are made without profiling. Let's just
check the sched_wake_date status before doing so.
---

diff --git a/src/stream.c b/src/stream.c
index 000a4c3fc5..fd9a027211 100644
--- a/src/stream.c
+++ b/src/stream.c
@@ -1639,8 +1639,12 @@ static void stream_handle_timeouts(struct stream *s)
  */
 static void stream_cond_update_cpu_latency(struct stream *s)
 {
-	uint32_t lat = th_ctx->sched_call_date - th_ctx->sched_wake_date;
+	uint32_t lat;
 
+	if (likely(!th_ctx->sched_wake_date))
+		return;
+
+	lat = th_ctx->sched_call_date - th_ctx->sched_wake_date;
 	s->lat_time += lat;
 }