Save a division, if delta is non-zero.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/stat.c b/stat.c
index 3b8fa367c2a936e7fb9d918b2872b4216feb6100..e974da77ff7ec557728daef9ea5c9e6243018af6 100644 (file)
--- a/stat.c
+++ b/stat.c
@@ -817,8 +817,10 @@ static inline void add_stat_sample(struct io_stat *is, unsigned long data)
                is->min_val = data;
 
        delta = val - is->mean;
                is->min_val = data;
 
        delta = val - is->mean;

-       is->mean += delta / (is->samples + 1.0);
-       is->S += delta * (val - is->mean);
+       if (delta) {
+               is->mean += delta / (is->samples + 1.0);
+               is->S += delta * (val - is->mean);
+       }

 
        is->samples++;
 }
 
        is->samples++;
 }