Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 5e38ca8f authored by Jiri Olsa's avatar Jiri Olsa Committed by Steven Rostedt
Browse files

tracing: Add unstable sched clock note to the warning 



The warning "Delta way too big" warning might appear on a system with
unstable shed clock right after the system is resumed and tracing
was enabled during the suspend.

Since it's not realy bug, and the unstable sched clock is working
fast and reliable otherwise, Steven suggested to keep using the
sched clock in any case and just to make note in the warning itself.

Signed-off-by: default avatarJiri Olsa <jolsa@redhat.com>
LKML-Reference: <1296649698-6003-1-git-send-email-jolsa@redhat.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent ae07f551

kernel/trace/ring_buffer.c

+6 −2
Original line number Diff line number Diff line
@@ -2163,10 +2163,14 @@ rb_reserve_next_event(struct ring_buffer *buffer, 
		delta = diff;

		if (unlikely(test_time_stamp(delta))) {

			WARN_ONCE(delta > (1ULL << 59),

				  KERN_WARNING "Delta way too big! %llu ts=%llu write stamp = %llu\n",

				  KERN_WARNING "Delta way too big! %llu ts=%llu write stamp = %llu\n%s",

				  (unsigned long long)delta,

				  (unsigned long long)ts,

				  (unsigned long long)cpu_buffer->write_stamp);

				  (unsigned long long)cpu_buffer->write_stamp,

				  sched_clock_stable ? "" :

				  "If you just came from a suspend/resume,\n"

				  "please switch to the trace global clock:\n"

				  "  echo global > /sys/kernel/debug/tracing/trace_clock\n");

			add_timestamp = 1;

		}

	}