[PATCH v2 2/2] trace: Mention trace_clock=global when warning about unstable clocks

From: Chris Wilson
Date: Fri Mar 30 2018 - 11:18:39 EST


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.

Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
kernel/trace/ring_buffer.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index dcf1c4dd3efe..88098d7fac06 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -2637,7 +2637,8 @@ 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;
}

--
2.16.3