zipf/pareto/gauss: add option to disable hashing

[fio.git] / lib / gauss.c

diff --git a/lib/gauss.c b/lib/gauss.c
index cd8b6e3e491a8669b3d5cad6e92c80567d656acb..48e2fbfef776ecd298a65e6771d3b4e797534693 100644 (file)
--- a/lib/gauss.c
+++ b/lib/gauss.c
@@ -15,7 +15,7 @@ static int gauss_dev(struct gauss_state *gs)
                return 0;
 
        r = __rand(&gs->r);
-       vr = gs->stddev * (r / (FRAND_MAX + 1.0));
+       vr = gs->stddev * (r / (FRAND32_MAX + 1.0));
 
        return vr - gs->stddev / 2;
 }
@@ -38,16 +38,27 @@ unsigned long long gauss_next(struct gauss_state *gs)
                sum += dev;
        }
 
-       return __hash_u64(sum) % gs->nranges;
+       if (!gs->disable_hash)
+               return __hash_u64(sum) % gs->nranges;
+
+       return sum % gs->nranges;
 }
 
-void gauss_init(struct gauss_state *gs, unsigned long nranges, unsigned int d,
+void gauss_init(struct gauss_state *gs, unsigned long nranges, double dev,
                unsigned int seed)
 {
        memset(gs, 0, sizeof(*gs));
-       init_rand_seed(&gs->r, seed);
+       init_rand_seed(&gs->r, seed, 0);
        gs->nranges = nranges;
-       gs->stddev = d;
-       if (gs->stddev > nranges / 2)
-               gs->stddev = nranges / 2;
+
+       if (dev != 0.0) {
+               gs->stddev = ceil((double) (nranges * 100.0) / dev);
+               if (gs->stddev > nranges / 2)
+                       gs->stddev = nranges / 2;
+       }
+}
+
+void gauss_disable_hash(struct gauss_state *gs)
+{
+       gs->disable_hash = true;
 }