diff options
Diffstat (limited to 'lib/math/mean_and_variance.c')
| -rw-r--r-- | lib/math/mean_and_variance.c | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/lib/math/mean_and_variance.c b/lib/math/mean_and_variance.c index f15aefc0b4d0..c0552828f8c3 100644 --- a/lib/math/mean_and_variance.c +++ b/lib/math/mean_and_variance.c @@ -57,6 +57,16 @@ inline s64 fast_divpow2(s64 n, u8 d) return (n + ((n < 0) ? ((1 << d) - 1) : 0)) >> d; // + (n < 0 ? 1 : 0); } +/* +inline u128 u128_mul(u128 a, u128 b) +{ + u32 a1 = a.lo, a2 = a.lo >> 32, a3 = a.hi, a4 = a.hi >> 32; + u32 b1 = b.lo, b2 = b.lo >> 32, b3 = b.hi, b4 = b.hi >> 32; + + + a1 * b1 + (a2 * b1) << 32 + (a1 + b2) << 32 + a2 * b2) +} +*/ /** * mean_and_variance_update() - update a mean_and_variance struct @s1 with a new sample @v1 * and return it. @@ -70,14 +80,15 @@ struct mean_and_variance mean_and_variance_update(struct mean_and_variance s1, s struct mean_and_variance s2; u64 v2 = abs(v1); + /* if (v2 > SQRT_U64_MAX) { v2 = SQRT_U64_MAX; WARN(true, "stats overflow! %lld^2 > U64_MAX", v1); } - + */ s2.n = s1.n + 1; s2.sum = s1.sum + v1; - s2.sum_squares = s1.sum_squares + v2*v2; + s2.sum_squares = u128_add(s1.sum_squares, u128_square(v2)); return s2; } EXPORT_SYMBOL_GPL(mean_and_variance_update); @@ -98,11 +109,11 @@ EXPORT_SYMBOL_GPL(mean_and_variance_get_mean); */ u64 mean_and_variance_get_variance(struct mean_and_variance s1) { - u64 s2 = s1.sum_squares / s1.n; - u64 s3 = abs(mean_and_variance_get_mean(s1)); + u128 s2 = u128_div(s1.sum_squares,s1.n); + u64 s3 = abs(mean_and_variance_get_mean(s1)); - WARN(s3 > SQRT_U64_MAX, "stats overflow %lld ^2 > S64_MAX", s3); - return s2 - s3*s3; + // WARN(s3 > SQRT_U64_MAX, "stats overflow %llu ^2 > S64_MAX", (u64)(s3 >> 64)); + return u128_sub(s2, u128_square(s3)).lo; } EXPORT_SYMBOL_GPL(mean_and_variance_get_variance); |