tracing: Mention trace_clock=global when warning about unstable clocks

Mention the alternative of adding trace_clock=global to the kernel
command line when we detect that we've used an unstable clock across a
suspend/resume cycle.

Link: http://lkml.kernel.org/r/20180330150132.16903-2-chris@chris-wilson.co.uk
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index a2fd3893cc02a7e42b3626cefeba608e21cb1c0a..515be03e30090653da36c0a2dce74c9a89b15334 100644 (file)
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -2731,7 +2731,8 @@ rb_handle_timestamp(struct ring_buffer_per_cpu *cpu_buffer,
                  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");
+                 "  echo global > /sys/kernel/debug/tracing/trace_clock\n"
+                 "or add trace_clock=global to the kernel command line\n");
        info->add_timestamp = 1;
 }