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#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/time.h>
#include "pagingtest.h"
#define LINESIZE 32
int thrashing_test(int test_runs, bool cache) {
int fds[4] = {-1, -1, -1, -1};
char tmpnames[4][17] = { "thrashing1XXXXXX", "thrashing2XXXXXX", "thrashing3XXXXXX", "thrashing4XXXXXX" };
volatile char *bufs[4] = {0};
unsigned long long k;
int ret = -1;
struct timeval begin_time, end_time, elapsed_time, total_time;
unsigned long long filesize;
long num_pages;
long pagesize;
timerclear(&total_time);
num_pages = sysconf(_SC_PHYS_PAGES);
pagesize = sysconf(_SC_PAGE_SIZE);
if (num_pages < 0) {
fprintf(stderr, "failed to get the number of pages\n");
return -1;
}
filesize = num_pages * pagesize / (ARRAY_SIZE(fds) - 1);
for (size_t i = 0; i < ARRAY_SIZE(fds); i++) {
fds[i] = create_tmp_file(tmpnames[i], filesize);
if (fds[i] < 0) {
goto err_fd;
}
}
for (size_t i = 0; i < ARRAY_SIZE(fds); i++) {
bufs[i] = mmap(NULL, filesize, PROT_READ, MAP_PRIVATE, fds[i], 0);
if (bufs[i] == ((void *)-1)) {
fprintf(stderr, "Failed to mmap file: %s\n", strerror(errno));
goto err;
}
if (!cache) {
//madvise and fadvise as random to prevent prefetching
ret = madvise((void *)bufs[i], filesize, MADV_RANDOM) ||
posix_fadvise(fds[i], 0, filesize, POSIX_FADV_RANDOM);
if (ret) {
goto err;
}
}
}
for (int i = 0; i < test_runs; i++) {
for (size_t j = 0; j < ARRAY_SIZE(fds); j++) {
gettimeofday(&begin_time, NULL);
for (k = 0; k < filesize; k += pagesize) {
bufs[j][k];
}
gettimeofday(&end_time, NULL);
timersub(&end_time, &begin_time, &elapsed_time);
timeradd(&total_time, &elapsed_time, &total_time);
}
}
printf("%scached thrashing: %llu MB/s\n", cache ? "" : "un",
(filesize * ARRAY_SIZE(fds) * test_runs * USEC_PER_SEC) /
(1024 * 1024 * (total_time.tv_sec * USEC_PER_SEC + total_time.tv_usec)));
ret = 0;
err:
for (size_t i = 0; i < ARRAY_SIZE(bufs) && bufs[i] != NULL; i++) {
munmap((void *)bufs[i], filesize);
}
err_fd:
for (size_t i = 0; i < ARRAY_SIZE(fds) && fds[i] >= 0; i++) {
close(fds[i]);
}
return ret;
}