X-Git-Url: https://git.kernel.dk/?p=fio.git;a=blobdiff_plain;f=lib%2Frand.c;h=0e787a62bad152568eee08824abf723716fec040;hp=1df1a7a049b9b14bb3c9334d4c2b7314e6168b07;hb=9dc528b1638b625b5e167983a74de4e85c5859ea;hpb=aa75fc9db6b98ad317911b35b4a968139a648bb8

diff --git a/lib/rand.c b/lib/rand.c
index 1df1a7a0..0e787a62 100644
--- a/lib/rand.c
+++ b/lib/rand.c
@@ -95,7 +95,7 @@ void init_rand_seed(struct frand_state *state, uint64_t seed, bool use64)
 		__init_rand64(&state->state64, seed);
 }
 
-void __fill_random_buf(void *buf, unsigned int len, uint64_t seed)
+void __fill_random_buf_small(void *buf, unsigned int len, uint64_t seed)
 {
 	uint64_t *b = buf;
 	uint64_t *e = b  + len / sizeof(*b);
@@ -103,13 +103,44 @@ void __fill_random_buf(void *buf, unsigned int len, uint64_t seed)
 
 	for (; b != e; ++b) {
 		*b = seed;
-		seed *= GOLDEN_RATIO_64;
+		seed = __hash_u64(seed);
 	}
 
 	if (fio_unlikely(rest))
 		__builtin_memcpy(e, &seed, rest);
 }
 
+void __fill_random_buf(void *buf, unsigned int len, uint64_t seed)
+{
+	static uint64_t prime[] = {1, 2, 3, 5, 7, 11, 13, 17,
+				   19, 23, 29, 31, 37, 41, 43, 47};
+	uint64_t *b, *e, s[CONFIG_SEED_BUCKETS];
+	unsigned int rest;
+	int p;
+
+	/*
+	 * Calculate the max index which is multiples of the seed buckets.
+	 */
+	rest = (len / sizeof(*b) / CONFIG_SEED_BUCKETS) * CONFIG_SEED_BUCKETS;
+
+	b = buf;
+	e = b + rest;
+
+	rest = len - (rest * sizeof(*b));
+
+	for (p = 0; p < CONFIG_SEED_BUCKETS; p++)
+		s[p] = seed * prime[p];
+
+	for (; b != e; b += CONFIG_SEED_BUCKETS) {
+		for (p = 0; p < CONFIG_SEED_BUCKETS; ++p) {
+			b[p] = s[p];
+			s[p] = __hash_u64(s[p]);
+		}
+	}
+
+	__fill_random_buf_small(b, rest, s[0]);
+}
+
 uint64_t fill_random_buf(struct frand_state *fs, void *buf,
 			 unsigned int len)
 {