We use do_div even though the divisor will usually be a power-of-two
unless there are unusual outliers. Use shifts where possible
Signed-off-by: Mel Gorman <mgor...@suse.de>
---
drivers/cpuidle/governors/menu.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index c4f80c1..801b2ee 100644
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -31,7 +31,8 @@
* The default values do not overflow.
*/
#define BUCKETS 12
-#define INTERVALS 8
+#define INTERVAL_SHIFT 3
+#define INTERVALS (1UL << INTERVAL_SHIFT)
#define RESOLUTION 1024
#define DECAY 8
#define MAX_INTERESTING 50000
@@ -228,7 +229,10 @@ again:
max = value;
}
}
- do_div(avg, divisor);
+ if (divisor == INTERVALS)
+ avg >>= INTERVAL_SHIFT;
+ else
+ do_div(avg, divisor);
/* Then try to determine standard deviation */
stddev = 0;
@@ -239,7 +243,11 @@ again:
stddev += diff * diff;
}
}
- do_div(stddev, divisor);
+ if (divisor == INTERVALS)
+ stddev >>= INTERVAL_SHIFT;
+ else
+ do_div(stddev, divisor);
+
/*
* The typical interval is obtained when standard deviation is small
* or standard deviation is small compared to the average interval.
--
1.8.4.5
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