[Assorted-commits] SF.net SVN: assorted: [398] numa-bench/trunk/src/malloc.cc

[<yan...@us...>]

Revision: 398
          http://assorted.svn.sourceforge.net/assorted/?rev=398&view=rev
Author:   yangzhang
Date:     2008-02-12 19:26:37 -0800 (Tue, 12 Feb 2008)

Log Message:
-----------
calling rand() in seq to make the test more fair; writing by ints not chars; added some notes

Modified Paths:
--------------
    numa-bench/trunk/src/malloc.cc

Modified: numa-bench/trunk/src/malloc.cc
===================================================================
--- numa-bench/trunk/src/malloc.cc	2008-02-12 22:15:13 UTC (rev 397)
+++ numa-bench/trunk/src/malloc.cc	2008-02-13 03:26:37 UTC (rev 398)
@@ -11,6 +11,8 @@
 //   - Huge difference. Also magnifies the locality effects more.
 //   - 1700 from local, 1990 from one neighbor, 2020 from another neighbor,
 //     and 2310 from remote.
+// - What's the difference between reading and writing?
+//   - TODO!
 // - Can we observe prefetching's effects? (Random access but chew the full
 //   cache line of data.)
 //   - TODO!
@@ -42,9 +44,10 @@
  *     shuffle the indexes we chew through.
  */
 void*
-chew(void* pp, int core, size_t size, int nreps, bool shuffle)
+chew(void* pp, unsigned int core, size_t size, unsigned int nreps, bool shuffle)
 {
-  char* p = (char*) pp;
+  int* p = (int*) pp;
+  const size_t count = size / sizeof(int);
   pid_t pid = gettid();
   timer t(": ");
 
@@ -56,15 +59,18 @@
 
   // Write sequentially to the memory region.
   if (shuffle) {
-    for (int c = 0; c < nreps; c++) {
-      for (size_t i = 0; i < size; i++) {
-        p[rand() % size] = i;
+    for (unsigned int c = 0; c < nreps; c++) {
+      for (size_t i = 0; i < count; i++) {
+        // NOTE: Using r as the index assumes that rand generates large-enough
+        // values.
+        int r = rand();
+        p[r % count] += r;
       }
     }
   } else {
-    for (int c = 0; c < nreps; c++) {
-      for (size_t i = 0; i < size; i++) {
-        p[i] = i;
+    for (unsigned int c = 0; c < nreps; c++) {
+      for (size_t i = 0; i < count; i++) {
+        p[i] += rand();
       }
     }
   }


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