Alexey Kopytov has proposed merging lp:~vadim-tk/sysbench/zipf-distribution
into lp:sysbench.
Requested reviews:
Alexey Kopytov (akopytov)
For more details, see:
https://code.launchpad.net/~vadim-tk/sysbench/zipf-distribution/+merge/104775
--
https://code.launchpad.net/~vadim-tk/sysbench/zipf-distribution/+merge/104775
Your team sysbench-developers is subscribed to branch lp:sysbench.
=== modified file 'sysbench/sysbench.c'
--- sysbench/sysbench.c 2012-03-21 08:20:02 +0000
+++ sysbench/sysbench.c 2012-05-04 16:56:19 +0000
@@ -81,7 +81,8 @@
{
DIST_TYPE_UNIFORM,
DIST_TYPE_GAUSSIAN,
- DIST_TYPE_SPECIAL
+ DIST_TYPE_SPECIAL,
+ DIST_TYPE_ZIPF
} rand_dist_t;
/* Event queue data type for the tx-rate mode */
@@ -99,6 +100,12 @@
static unsigned int rand_res;
static int rand_seed; /* optional seed set on the command line */
+/* parameters for zipf distribution */
+static double zipf_theta; /* parameter theta */
+static unsigned int zipf_nitems = 0; /* number of items to choose from */
+static double zipf_zetan; /* precalculated ZetaN, based on nitems */
+static double zipf_zeta2; /* precalculated Zeta2, based on theta */
+
/* Random seed used to generate unique random numbers */
static unsigned long long rnd_seed;
/* Mutex to protect random seed */
@@ -131,13 +138,14 @@
{"help", "print help and exit", SB_ARG_TYPE_FLAG, NULL},
{"version", "print version and exit", SB_ARG_TYPE_FLAG, "off"},
{"rand-init", "initialize random number generator", SB_ARG_TYPE_FLAG, "off"},
- {"rand-type", "random numbers distribution {uniform,gaussian,special}", SB_ARG_TYPE_STRING,
+ {"rand-type", "random numbers distribution {uniform,gaussian,special,zipf}", SB_ARG_TYPE_STRING,
"special"},
{"rand-spec-iter", "number of iterations used for numbers generation", SB_ARG_TYPE_INT, "12"},
{"rand-spec-pct", "percentage of values to be treated as 'special' (for special distribution)",
SB_ARG_TYPE_INT, "1"},
{"rand-spec-res", "percentage of 'special' values to use (for special distribution)",
SB_ARG_TYPE_INT, "75"},
+ {"rand-zipf-t", "parameter theta for zipf distibution", SB_ARG_TYPE_FLOAT, "1.16"},
{"rand-seed", "seed for random number generator, ignored when 0", SB_ARG_TYPE_INT, "0"},
{NULL, NULL, SB_ARG_TYPE_NULL, NULL}
};
@@ -1020,6 +1028,11 @@
rand_type = DIST_TYPE_SPECIAL;
rand_func = &sb_rand_special;
}
+ else if (!strcmp(s, "zipf"))
+ {
+ rand_type = DIST_TYPE_ZIPF;
+ rand_func = &sb_rand_zipf;
+ }
else
{
log_text(LOG_FATAL, "Invalid random numbers distribution: %s.", s);
@@ -1030,6 +1043,9 @@
rand_pct = sb_get_value_int("rand-spec-pct");
rand_res = sb_get_value_int("rand-spec-res");
+ zipf_theta = sb_get_value_float("rand-zipf-t");
+ zipf_zeta2 = sb_rand_zeta(2., zipf_theta);
+
sb_globals.tx_rate = sb_get_value_int("tx-rate");
sb_globals.report_interval = sb_get_value_int("report-interval");
@@ -1226,6 +1242,54 @@
return a + sum / rand_iter;
}
+/* zipf distribution */
+
+/* aux function to calculate zeta */
+double sb_rand_zeta(int n, double theta)
+{
+ int i;
+ double ans=0.0;
+
+ for (i=1; i <= n; i++)
+ ans += pow(1./(double)i, theta);
+ return(ans);
+}
+
+
+int sb_rand_zipf(int a, int b)
+{
+
+ double alpha, eta, rand_uni, rand_z;
+ unsigned int n;
+ unsigned int val;
+
+ n = b - a + 1;
+
+ /* we pre-cache zipf_zetan, as calculation is slow */
+ if (n != zipf_nitems)
+ {
+ zipf_zetan = sb_rand_zeta(n, zipf_theta);
+ zipf_nitems = n;
+ }
+
+ alpha = 1. / (1. - zipf_theta);
+ eta = (1. - pow(2./n, 1. - zipf_theta)) / (1. - zipf_zeta2/zipf_zetan);
+
+ rand_uni = (double) sb_rnd() / (double) SB_MAX_RND;
+ rand_z = rand_uni * zipf_zetan;
+
+ if (rand_z < 1.)
+ {
+ val = 1;
+ } else if (rand_z < (1. + pow(0.5, zipf_theta))) {
+ val = 2;
+ } else {
+ val = 1 + (unsigned int)(n * pow(eta*rand_uni - eta + 1., alpha));
+ }
+
+ return a + val - 1;
+}
+
/* 'special' distribution */
int sb_rand_special(int a, int b)
=== modified file 'sysbench/sysbench.h'
--- sysbench/sysbench.h 2012-03-18 22:35:16 +0000
+++ sysbench/sysbench.h 2012-05-04 16:56:19 +0000
@@ -227,6 +227,8 @@
int sb_rand_uniform(int, int);
int sb_rand_gaussian(int, int);
int sb_rand_special(int, int);
+int sb_rand_zipf(int, int);
+double sb_rand_zeta(int n, double theta);
int sb_rand_uniq(int a, int b);
void sb_rand_str(const char *, char *);
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