diff options
Diffstat (limited to 'usr/src/lib/libdtrace/common')
| -rw-r--r-- | usr/src/lib/libdtrace/common/dt_consume.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/usr/src/lib/libdtrace/common/dt_consume.c b/usr/src/lib/libdtrace/common/dt_consume.c index b292b6abc5..7f8c673dbe 100644 --- a/usr/src/lib/libdtrace/common/dt_consume.c +++ b/usr/src/lib/libdtrace/common/dt_consume.c @@ -381,8 +381,10 @@ dt_stddev(uint64_t *data, uint64_t normal) * The standard approximation for standard deviation is * sqrt(average(x**2) - average(x)**2), i.e. the square root * of the average of the squares minus the square of the average. + * When normalizing, we should divide the sum of x**2 by normal**2. */ dt_divide_128(data + 2, normal, avg_of_squares); + dt_divide_128(avg_of_squares, normal, avg_of_squares); dt_divide_128(avg_of_squares, data[0], avg_of_squares); norm_avg = (int64_t)data[1] / (int64_t)normal / (int64_t)data[0]; |