From ce5ced411e25d99e026aac0d907f01055c1a3e89 Mon Sep 17 00:00:00 2001
From: Timo Kokkonen <kaapeli@ee.oulu.fi>
Date: Thu, 15 May 2008 19:12:37 +0300
Subject: [PATCH] Initial commit

---
 Makefile   | 11 ++++++
 membench.c | 98 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 109 insertions(+)
 create mode 100644 Makefile
 create mode 100644 membench.c

diff --git a/Makefile b/Makefile
new file mode 100644
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
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;
+}
-- 
2.44.0