perf/core: Change log level for duration warning to KERN_INFO

David Ahern · Ingo Molnar · commit 0d87d7ec22a0 · 2016-08-02T10:23:57.000+02:00
When the perf interrupt handler exceeds a threshold warning messages are displayed on console: [12739.31793] perf interrupt took too long (2504 > 2500), lowering kernel.perf_event_max_sample_rate to 50000 [71340.165065] perf interrupt took too long (5005 > 5000), lowering kernel.perf_event_max_sample_rate to 25000 Many customers and users are confused by the message wondering if something is wrong or they need to take action to fix a problem. Since a user can not do anything to fix the issue, the message is really more informational than a warning. Adjust the log level accordingly. Signed-off-by: David Ahern <dsa@cumulusnetworks.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1470084569-438-1-git-send-email-dsa@cumulusnetworks.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/kernel/events/core.c b/kernel/events/core.c
@@ -448,7 +448,7 @@ static u64 __report_allowed;
 
 static void perf_duration_warn(struct irq_work *w)
 {
-	printk_ratelimited(KERN_WARNING
+	printk_ratelimited(KERN_INFO
 		"perf: interrupt took too long (%lld > %lld), lowering "
 		"kernel.perf_event_max_sample_rate to %d\n",
 		__report_avg, __report_allowed,

Original file line number	Diff line number	Diff line change
`@@ -448,7 +448,7 @@ static u64 __report_allowed;`
`448`	`448`
`449`	`449`	`static void perf_duration_warn(struct irq_work *w)`
`450`	`450`	`{`
`451`		`- printk_ratelimited(KERN_WARNING`
	`451`	`+ printk_ratelimited(KERN_INFO`
`452`	`452`	`"perf: interrupt took too long (%lld > %lld), lowering "`
`453`	`453`	`"kernel.perf_event_max_sample_rate to %d\n",`
`454`	`454`	`__report_avg, __report_allowed,`