From 9b5553a5a46045658faf15680d4272f8e446fd84 Mon Sep 17 00:00:00 2001
From: Sathya Narayanan <sramamir@eng.ucsd.edu>
Date: Tue, 23 Feb 2016 00:07:37 -0800
Subject: [PATCH] Memory access time

---
 memory_access_time.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)
 create mode 100644 memory_access_time.c

diff --git a/memory_access_time.c b/memory_access_time.c
new file mode 100644
index 0000000..a173fe5
--- /dev/null
+++ b/memory_access_time.c
@@ -0,0 +1,45 @@
+#include<stdio.h>
+#include <sys/time.h>
+#include <stdlib.h>
+
+#define KB 1024
+#define MB 1024 * KB
+#define MAX_ARRAY_SIZE 32*MB
+#define STRIDE_SIZE 16
+#define CPU_FREQ 900
+
+typedef unsigned long long int u64;
+
+u64 access_time_1(u64 size, int stride_size){
+	struct timeval start, end;
+	struct timezone tz;
+
+    int *array = (int *)malloc(size);
+    int len = (size)/sizeof(int);
+    unsigned int i;
+
+	gettimeofday(&start, &tz);
+   	for(i=0; i < MAX_ARRAY_SIZE; i++) {
+       array[( i * stride_size) % len]++;
+    }
+	gettimeofday(&end, &tz);
+   
+    free(array);
+	return ((end.tv_sec * 1e6) + end.tv_usec - (start.tv_sec * 1e6) - start.tv_usec);
+}
+ 
+int main()
+{
+	int i, j;
+
+	for (j = 4; j <= 32; j*=2) {
+		printf("Stride size: %u\n", j);
+		for (i = 1024; i <= 32 * MB; i*=2) {
+			u64 access_time = access_time_1(i, j);
+			u64 overhead = 10;
+			double avg = (access_time * 1000.0)/(2 * MAX_ARRAY_SIZE);
+			printf("Size: %uKB access: %lluus, avg: %gns\n", i >> 10, access_time, avg - overhead);
+		}
+	}
+	return 0;
+}
-- 
1.9.1