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Commit 90b06817c375bdb49bf9729029b96a982fbd6792

Authored by Aravind Kumar
1 parent 5c68199029
Exists in master

Memory access time

Showing 3 changed files with 66 additions and 14 deletions Side-by-side Diff

memory/memory_access_time.c View file @ 90b0681
... ... @@ -4,11 +4,11 @@
4 4  
5 5 #define KB 1024
6 6 #define MB 1024 * KB
7   -#define MAX_ARRAY_SIZE 32*MB
  7 +#define MAX_ITERATIONS 1000000
8 8 #define STRIDE_SIZE 16
9 9 #define CPU_FREQ 900
10 10  
11   -unsigned long long access_time_1(int size, int stride_size){
  11 +unsigned long long func(int size, int stride_size){
12 12 struct timeval start, end;
13 13 struct timezone tz;
14 14 unsigned long long time1, time2;
15 15  
16 16  
17 17  
18 18  
19 19  
20 20  
... ... @@ -16,35 +16,35 @@
16 16 int *array = (int *)malloc(size);
17 17 int len = (size)/sizeof(int);
18 18 unsigned int i;
19   - for(i=0; i < MAX_ARRAY_SIZE; i++) {
  19 + for(i=0; i < MAX_ITERATIONS; i++) {
20 20 array[( i * stride_size) % len] = array[( i * stride_size) % len]+i;
21 21 }
22 22  
23   - gettimeofday(&start, NULL);
24   - //asm volatile("mrc p15, 0, %0, c9, c13, 0" : "=r" (time1));
25   - for(i=0; i < MAX_ARRAY_SIZE; i++) {
  23 + //gettimeofday(&start, NULL);
  24 + asm volatile("mrc p15, 0, %0, c9, c13, 0" : "=r" (time1));
  25 + for(i=0; i < MAX_ITERATIONS; i++) {
26 26 j = array[( i * stride_size) % len];
27 27 }
28   - gettimeofday(&end, NULL);
29   - //asm volatile("mrc p15, 0, %0, c9, c13, 0" : "=r" (time2));
  28 + //gettimeofday(&end, NULL);
  29 + asm volatile("mrc p15, 0, %0, c9, c13, 0" : "=r" (time2));
30 30  
31 31 free(array);
32   - //return time2-time1;
33   - return (-start.tv_sec*1e6-start.tv_usec+end.tv_sec*1e6+end.tv_usec);
  32 + return time2 - time1;
  33 + //return (-start.tv_sec*1e6-start.tv_usec+end.tv_sec*1e6+end.tv_usec);
34 34 }
35 35  
36 36 int main()
37 37 {
38 38 int i, j;
39 39  
40   - for (j = 128; j <= 1024; j*=2) {
  40 + for (j = 16; j <= 1024; j*=2) {
41 41 printf("Stride size: %u\n", j);
42 42 for (i = 1024; i <= 32 * MB; i*=2) {
43   - unsigned long long access_time = access_time_1(i, j);
  43 + unsigned long long access_time = func(i, j);
44 44 //unsigned overhead = 10;
45 45 //multiply access time by 1000 to convert to ns
46   - //double avg = (access_time * 1.111)/(MAX_ARRAY_SIZE);
47   - double avg = (access_time * 1000.0)/(MAX_ARRAY_SIZE);
  46 + //double avg = (access_time * 1.111)/(MAX_ITERATIONS);
  47 + double avg = (access_time * 1000.0)/(MAX_ITERATIONS);
48 48 printf("Size: %uKB access: %lluus, avg: %gns\n", i >> 10, access_time, avg);
49 49 }
50 50 }
memory/memory_access_time_overhead.c View file @ 90b0681
  1 +#include<stdio.h>
  2 +#include <sys/time.h>
  3 +#include <stdlib.h>
  4 +
  5 +#define KB 1024
  6 +#define MB 1024 * KB
  7 +#define MAX_ITERATIONS 1000000
  8 +#define STRIDE_SIZE 16
  9 +#define CPU_FREQ 900
  10 +
  11 +unsigned long long func(int size, int stride_size){
  12 + struct timeval start, end;
  13 + struct timezone tz;
  14 + unsigned long long time1, time2;
  15 + int j;
  16 + int *array = (int *)malloc(size);
  17 + int len = (size)/sizeof(int);
  18 + unsigned int i;
  19 + for(i=0; i < MAX_ITERATIONS; i++) {
  20 + array[( i * stride_size) % len] = array[( i * stride_size) % len]+i;
  21 + }
  22 +
  23 + //gettimeofday(&start, NULL);
  24 + asm volatile("mrc p15, 0, %0, c9, c13, 0" : "=r" (time1));
  25 + for(i=0; i < MAX_ITERATIONS; i++) {
  26 + j = ( i * stride_size) % len;
  27 + }
  28 + //gettimeofday(&end, NULL);
  29 + asm volatile("mrc p15, 0, %0, c9, c13, 0" : "=r" (time2));
  30 +
  31 + free(array);
  32 + return time2 - time1;
  33 + //return (-start.tv_sec*1e6-start.tv_usec+end.tv_sec*1e6+end.tv_usec);
  34 +}
  35 +
  36 +int main()
  37 +{
  38 + int i, j;
  39 +
  40 + for (j = 16; j <= 1024; j*=2) {
  41 + printf("Stride size: %u\n", j);
  42 + for (i = 1024; i <= 32 * MB; i*=2) {
  43 + unsigned long long access_time = func(i, j);
  44 + //unsigned overhead = 10;
  45 + //multiply access time by 1000 to convert to ns
  46 + //double avg = (access_time * 1.111)/(MAX_ITERATIONS);
  47 + double avg = (access_time * 1000.0)/(MAX_ITERATIONS);
  48 + printf("Size: %uKB access: %lluus, avg: %gns\n", i >> 10, access_time, avg);
  49 + }
  50 + }
  51 + return 0;
  52 +}
memory/memory_access_time_overhead_new.o View file @ 90b0681

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