improved perf_test to measure steady state behavior

[nbds] / runtime / runtime.c

diff --git a/runtime/runtime.c b/runtime/runtime.c
index 415a1617816f18133728538b7059bf1b89ee9980..fe4a1bd894a6dc09d776ffbbb8276d1f7ce2605f 100644 (file)
--- a/runtime/runtime.c
+++ b/runtime/runtime.c
@@ -1,4 +1,4 @@
-/* 
+/*
  * Written by Josh Dybnis and released to the public domain, as explained at
  * http://creativecommons.org/licenses/publicdomain
  */
@@ -12,7 +12,10 @@
 #include "tls.h"
 
 DECLARE_THREAD_LOCAL(tid_, int);
-DECLARE_THREAD_LOCAL(rand_seed_, unsigned);
+DECLARE_THREAD_LOCAL(rx_, uint32_t);
+DECLARE_THREAD_LOCAL(ry_, uint32_t);
+DECLARE_THREAD_LOCAL(rz_, uint32_t);
+DECLARE_THREAD_LOCAL(rc_, uint32_t);
 
 typedef struct thread_info {
     int thread_id;
@@ -21,26 +24,28 @@ typedef struct thread_info {
 } thread_info_t;
 
 __attribute__ ((constructor)) void nbd_init (void) {
-    //sranddev();
-    INIT_THREAD_LOCAL(rand_seed_);
+    INIT_THREAD_LOCAL(r);
     INIT_THREAD_LOCAL(tid_);
     SET_THREAD_LOCAL(tid_, 0);
     mem_init();
     lwt_thread_init(0);
     rcu_thread_init(0);
+    srand((uint32_t)rdtsc());
 }
 
 static void *worker (void *arg) {
     thread_info_t *ti = (thread_info_t *)arg;
     SET_THREAD_LOCAL(tid_, ti->thread_id);
     LOCALIZE_THREAD_LOCAL(tid_, int);
-#ifndef NDEBUG
-    SET_THREAD_LOCAL(rand_seed_, tid_+1);
-#else
-    SET_THREAD_LOCAL(rand_seed_, nbd_rand_seed(tid_+1));
-#endif
+
+    SET_THREAD_LOCAL(rx_, rand());
+    SET_THREAD_LOCAL(ry_, rand());
+    SET_THREAD_LOCAL(rz_, rand());
+    SET_THREAD_LOCAL(rc_, rand());
+
     lwt_thread_init(ti->thread_id);
     rcu_thread_init(ti->thread_id);
+
     void *ret = ti->start_routine(ti->arg);
     nbd_free(ti);
     return ret;
@@ -54,18 +59,35 @@ int nbd_thread_create (pthread_t *restrict thread, int thread_id, void *(*start_
     return pthread_create(thread, NULL, worker, ti);
 }
 
-int nbd_rand (void) {
-    LOCALIZE_THREAD_LOCAL(rand_seed_, unsigned);
-    unsigned r = rand_r(&rand_seed_);
-    SET_THREAD_LOCAL(rand_seed_, r);
+// George Marsaglia's KISS generator
+uint64_t nbd_rand (void) {
+    LOCALIZE_THREAD_LOCAL(rx_, unsigned);
+    LOCALIZE_THREAD_LOCAL(ry_, unsigned);
+    LOCALIZE_THREAD_LOCAL(rz_, unsigned);
+    LOCALIZE_THREAD_LOCAL(rc_, unsigned);
+
+    uint32_t rx = 69069 * rx_ + 12345;
+    uint32_t ry = ry_;
+    uint32_t rz = rz_;
+    ry ^= (ry << 13);
+    ry ^= (ry >> 17);
+    ry ^= (ry <<  5);
+    uint64_t t = rz * 698769069LL + rc_;
+    uint64_t r = rx + ry + (rz = t);
+
+    SET_THREAD_LOCAL(rx_, rx);
+    SET_THREAD_LOCAL(ry_, ry);
+    SET_THREAD_LOCAL(rz_, rz);
+    SET_THREAD_LOCAL(rc_, t >> 32);
+
     return r;
 }
 
+// Fairly fast random numbers
 uint64_t nbd_rand_seed (int i) {
     return rdtsc() + -715159705 + i * 129;
 }
 
-// Fairly fast random numbers
 int nbd_next_rand (uint64_t *r) {
     *r = (*r * 0x5DEECE66DLL + 0xBLL) & MASK(48);
     return (*r >> 17) & 0x7FFFFFFF;