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From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	David Daney <ddaney.cavm@gmail.com>
Subject: [for-next][PATCH 2/6] tracing: Convert stddev into u64 in tracepoint benchmark
Date: Fri, 06 Jun 2014 12:30:36 -0400	[thread overview]
Message-ID: <20140606172104.347167544@goodmis.org> (raw)
In-Reply-To: 20140606163034.516780857@goodmis.org

[-- Attachment #1: 0001-tracing-Convert-stddev-into-u64-in-tracepoint-benchm.patch --]
[-- Type: text/plain, Size: 980 bytes --]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

I've been told that do_div() expects an unsigned 64 bit number, and
is undefined if a signed is used. This gave a warning on the MIPS
build. I'm not sure if a signed 64 bit dividend is really an issue
or not, but the calculation this is used for is standard deviation,
and that isn't going to be negative. We can just convert it to
unsigned and be safe.

Reported-by: David Daney <ddaney.cavm@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_benchmark.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace_benchmark.c b/kernel/trace/trace_benchmark.c
index a10adc7095cd..8bd3365a65b2 100644
--- a/kernel/trace/trace_benchmark.c
+++ b/kernel/trace/trace_benchmark.c
@@ -33,7 +33,7 @@ static void trace_do_benchmark(void)
 	u64 start;
 	u64 stop;
 	u64 delta;
-	s64 stddev;
+	u64 stddev;
 	u64 seed;
 	u64 last_seed;
 	unsigned int avg;
-- 
2.0.0.rc2



  parent reply	other threads:[~2014-06-06 17:21 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-06-06 16:30 [for-next][PATCH 0/6] tracing: Hopefully the last updates for 3.16 merge window Steven Rostedt
2014-06-06 16:30 ` [for-next][PATCH 1/6] tracing: Introduce saved_cmdlines_size file Steven Rostedt
2014-06-06 16:30 ` Steven Rostedt [this message]
2014-06-06 16:30 ` [for-next][PATCH 3/6] tracing: Only calculate stats of tracepoint benchmarks for 2^32 times Steven Rostedt
2014-06-10  5:17   ` Namhyung Kim
2014-06-10 12:16     ` Steven Rostedt
2014-06-10 13:42     ` Steven Rostedt
2014-06-10 16:12       ` Steven Rostedt
2014-06-06 16:30 ` [for-next][PATCH 4/6] tracing: Return error if ftrace_trace_arrays list is empty Steven Rostedt
2014-06-10  5:20   ` Namhyung Kim
2014-06-10 13:42     ` Steven Rostedt
2014-06-06 16:30 ` [for-next][PATCH 5/6] tracing/kprobes: Avoid self tests if tracing is disabled on boot up Steven Rostedt
2014-06-06 16:30 ` [for-next][PATCH 6/6] tracing: Fix leak of ring buffer data when new instances creation fails Steven Rostedt
2014-06-10  5:25   ` Namhyung Kim
2014-06-10 15:58     ` Steven Rostedt

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