Initial commit

diff --git a/Makefile b/Makefile
new file mode 100644 (file)
index 0000000..020465e
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,11 @@
+CFLAGS=-Wall -O2 -g
+
+membench: membench.c
+       gcc $CFLAGS membench.c -o membench
+
+all: membench
+
+clean:
+       rm -rf membench *~
+
+.PHONY: all clean TAGS

diff --git a/membench.c b/membench.c
new file mode 100644 (file)
index 0000000..7cad40b
--- /dev/null
+++ b/membench.c
@@ -0,0 +1,98 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/time.h>
+
+#define lsize sizeof(unsigned long)
+
+long usec_diff(const struct timeval *a, const struct timeval *b)
+{
+       long usec_a, usec_b;
+       usec_a = a->tv_sec * 1000000 + a->tv_usec;
+       usec_b = b->tv_sec * 1000000 + b->tv_usec;
+       return usec_b - usec_a;
+}
+
+int main(int argc, char *argv[])
+{
+       int iterations, j, k, count, size;
+       unsigned long *buf, i, tmp = 0;
+       struct timeval start, end;
+
+       if (argc > 1)
+               iterations = atoi(argv[1]);
+       else
+               iterations = 24;
+
+       if (argc > 2)
+               count = atoi(argv[2]) * 1024;
+       else
+               count = 1024;
+
+       printf("Doing %d runs with buffer size goin up to %dk\n",
+              iterations, 1 << (iterations - 10));
+       printf("Running each round %d times\n", count);
+       printf("Size of unsigned long is %lu bits\n", lsize * 8);
+
+       switch (lsize) {
+       case 4:
+               j = 12;
+               break;
+       case 8:
+               j = 10;
+               break;
+       default:
+               printf("WTF?\n");
+               exit(1);
+       }
+
+       for (; j < iterations + 1; j++) {
+               size = (1 << j) / lsize;
+               buf = malloc(size * lsize);
+
+               if (buf == NULL) {
+                       printf("Malloc failed\n");
+                       exit(1);
+               }
+
+               /* Touch the pages */
+               for (i = 0; i < size; i++)
+                       buf[i] = i;
+
+               printf("%luk\t", size * lsize / 1024);
+
+               printf("read: ");
+               fflush(stdout);
+
+               gettimeofday(&start, 0);
+               for (k = 0; k < count; k++) {
+                       buf[0] = tmp;
+                       for (i = 0; i < size; i++)
+                               tmp += buf[i];
+               }
+
+               gettimeofday(&end, 0);
+
+               printf("% 9.2f MB/s ", (double)(size * lsize) * 
+                      (1000000 / (1024.0 * 1024.0)) * count / 
+                      (double) usec_diff(&start, &end));
+
+
+               printf("write: ");
+               fflush(stdout);
+
+               gettimeofday(&start, 0);
+               for (k = 0; k < count; k++)
+                       for (i = 0; i < size; i++)
+                                buf[i] = i;
+               gettimeofday(&end, 0);
+
+               printf("% 9.2f MB/s ", (double)(size * lsize) * 
+                      (1000000 / (1024.0 * 1024.0)) * count / 
+                      (double) usec_diff(&start, &end));
+       
+               printf("\n");
+
+               free(buf);
+       }
+       return 0;
+}