linux-kernel - [PATCH] perf: Change log level for duration warning to INFO

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Message-Id: <1470084569-438-1-git-send-email-dsa@cumulusnetworks.com>
Date:	Mon,  1 Aug 2016 13:49:29 -0700
From:	David Ahern <dsa@...ulusnetworks.com>
To:	peterz@...radead.org, mingo@...nel.org
Cc:	linux-kernel@...r.kernel.org, David Ahern <dsa@...ulusnetworks.com>
Subject: [PATCH] perf: Change log level for duration warning to INFO

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@...ulusnetworks.com>
---
 kernel/events/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 356a6c7cb52a..a19550d80ab1 100644
--- 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,
-- 
2.1.4