lib/rand: improve __fill_random_buf()

This won't be equivalent to what we have, but I _think_ the randomness
is good enough for this purpose.

This improves performance by about 30% for me, tested on both aarch64
and x86-64.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/lib/rand.c b/lib/rand.c
index 2243c2b4342caed6e1983f52bd0c32ff9c024df4..1df1a7a049b9b14bb3c9334d4c2b7314e6168b07 100644 (file)
--- a/lib/rand.c
+++ b/lib/rand.c
@@ -103,8 +103,7 @@ void __fill_random_buf(void *buf, unsigned int len, uint64_t seed)
 
        for (; b != e; ++b) {
                *b = seed;
-               seed *= GOLDEN_RATIO_PRIME;
-               seed >>= 3;
+               seed *= GOLDEN_RATIO_64;
        }
 
        if (fio_unlikely(rest))