lib/rand: get rid of unused MAX_SEED_BUCKETS

[fio.git] / lib / rand.c

diff --git a/lib/rand.c b/lib/rand.c
index 2243c2b4342caed6e1983f52bd0c32ff9c024df4..0e787a62bad152568eee08824abf723716fec040 100644 (file)
--- 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);
@@ -103,14 +103,44 @@ 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 = __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)
 {