Random distribution 32-bit fixes

[fio.git] / lib / zipf.c

diff --git a/lib/zipf.c b/lib/zipf.c
index c691bc51a5a57f6e84ef2450d47fb0ad12f02bcc..321a4fb9645e8995e1145758ec75530aeea75a16 100644 (file)
--- a/lib/zipf.c
+++ b/lib/zipf.c
@@ -1,12 +1,5 @@
 #include <math.h>
 #include <string.h>
-#include <inttypes.h>
-#include <stdio.h>
-#include <unistd.h>
-#include <sys/types.h>
-#include <fcntl.h>
-#include "ieee754.h"
-#include "../log.h"
 #include "zipf.h"
 #include "../minmax.h"
 #include "../hash.h"
@@ -15,7 +8,7 @@
 
 static void zipf_update(struct zipf_state *zs)
 {
-       unsigned long to_gen;
+       uint64_t to_gen;
        unsigned int i;
 
        /*
@@ -29,17 +22,17 @@ static void zipf_update(struct zipf_state *zs)
                zs->zetan += pow(1.0 / (double) (i + 1), zs->theta);
 }
 
-static void shared_rand_init(struct zipf_state *zs, unsigned long nranges,
+static void shared_rand_init(struct zipf_state *zs, uint64_t nranges,
                             unsigned int seed)
 {
        memset(zs, 0, sizeof(*zs));
        zs->nranges = nranges;
 
-       init_rand_seed(&zs->rand, seed);
+       init_rand_seed(&zs->rand, seed, 0);
        zs->rand_off = __rand(&zs->rand);
 }
 
-void zipf_init(struct zipf_state *zs, unsigned long nranges, double theta,
+void zipf_init(struct zipf_state *zs, uint64_t nranges, double theta,
               unsigned int seed)
 {
        shared_rand_init(zs, nranges, seed);
@@ -50,7 +43,7 @@ void zipf_init(struct zipf_state *zs, unsigned long nranges, double theta,
        zipf_update(zs);
 }
 
-unsigned long long zipf_next(struct zipf_state *zs)
+uint64_t zipf_next(struct zipf_state *zs)
 {
        double alpha, eta, rand_uni, rand_z;
        unsigned long long n = zs->nranges;
@@ -59,7 +52,7 @@ unsigned long long zipf_next(struct zipf_state *zs)
        alpha = 1.0 / (1.0 - zs->theta);
        eta = (1.0 - pow(2.0 / n, 1.0 - zs->theta)) / (1.0 - zs->zeta2 / zs->zetan);
 
-       rand_uni = (double) __rand(&zs->rand) / (double) FRAND_MAX;
+       rand_uni = (double) __rand(&zs->rand) / (double) FRAND32_MAX;
        rand_z = rand_uni * zs->zetan;
 
        if (rand_z < 1.0)
@@ -69,20 +62,35 @@ unsigned long long zipf_next(struct zipf_state *zs)
        else
                val = 1 + (unsigned long long)(n * pow(eta*rand_uni - eta + 1.0, alpha));
 
-       return (__hash_u64(val - 1) + zs->rand_off) % zs->nranges;
+       val--;
+
+       if (!zs->disable_hash)
+               val = __hash_u64(val);
+
+       return (val + zs->rand_off) % zs->nranges;
 }
 
-void pareto_init(struct zipf_state *zs, unsigned long nranges, double h,
+void pareto_init(struct zipf_state *zs, uint64_t nranges, double h,
                 unsigned int seed)
 {
        shared_rand_init(zs, nranges, seed);
        zs->pareto_pow = log(h) / log(1.0 - h);
 }
 
-unsigned long long pareto_next(struct zipf_state *zs)
+uint64_t pareto_next(struct zipf_state *zs)
 {
-       double rand = (double) __rand(&zs->rand) / (double) FRAND_MAX;
-       unsigned long long n = zs->nranges - 1;
+       double rand = (double) __rand(&zs->rand) / (double) FRAND32_MAX;
+       unsigned long long n;
+
+       n = (zs->nranges - 1) * pow(rand, zs->pareto_pow);
+
+       if (!zs->disable_hash)
+               n = __hash_u64(n);
 
-       return (__hash_u64(n * pow(rand, zs->pareto_pow)) + zs->rand_off) % zs->nranges;
+       return (n + zs->rand_off)  % zs->nranges;
+}
+
+void zipf_disable_hash(struct zipf_state *zs)
+{
+       zs->disable_hash = true;
 }