/*
* Copyright (C) 2010 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/* A simple test of emmc random read and write performance. When testing write
* performance, try it twice, once with O_SYNC compiled in, and once with it commented
* out. Without O_SYNC, the close(2) blocks until all the dirty buffers are written
* out, but the numbers tend to be higher.
*/
#define _LARGEFILE64_SOURCE
#include <string.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/time.h>
#include <stdlib.h>
#include <unistd.h>
#include <math.h>
#define TST_BLK_SIZE 4096
/* Number of seconds to run the test */
#define TEST_LEN 10
struct stats {
struct timeval start;
struct timeval end;
off64_t offset;
};
static void usage(void) {
fprintf(stderr, "Usage: rand_emmc_perf [ -r | -w ] [-o] [-s count] [-f full_stats_filename] <size_in_mb> <block_dev>\n");
exit(1);
}
static void print_stats(struct stats *stats_buf, int stats_count,
char * full_stats_file)
{
int i;
struct timeval t;
struct timeval sum = { 0, 0 };
struct timeval max = { 0, 0 };
long long total_usecs;
long long avg_usecs;
long long max_usecs;
long long variance = 0;;
long long x;
double sdev;
FILE *full_stats = NULL;
if (full_stats_file) {
full_stats = fopen(full_stats_file, "w");
if (full_stats == NULL) {
fprintf(stderr, "Cannot open full stats output file %s, ignoring\n",
full_stats_file);
}
}
for (i = 0; i < stats_count; i++) {
timersub(&stats_buf[i].end, &stats_buf[i].start, &t);
if (timercmp(&t, &max, >)) {
max = t;
}
if (full_stats) {
fprintf(full_stats, "%lld\n", (t.tv_sec * 1000000LL) + t.tv_usec);
}
timeradd(&sum, &t, &sum);
}
if (full_stats) {
fclose(full_stats);
}
max_usecs = (max.tv_sec * 1000000LL) + max.tv_usec;
total_usecs = (sum.tv_sec * 1000000LL) + sum.tv_usec;
avg_usecs = total_usecs / stats_count;
printf("average random %d byte iop time = %lld usecs\n",
TST_BLK_SIZE, avg_usecs);
printf("maximum random %d byte iop time = %lld usecs\n",
TST_BLK_SIZE, max_usecs);
/* Now that we have the average (aka mean) go through the data
* again and compute the standard deviation.
* The formula is sqrt(sum_1_to_n((Xi - avg)^2)/n)
*/
for (i = 0; i < stats_count; i++) {
timersub(&stats_buf[i].end, &stats_buf[i].start, &t); /* Xi */
x = (t.tv_sec * 1000000LL) + t.tv_usec; /* Convert to long long */
x = x - avg_usecs; /* Xi - avg */
x = x * x; /* (Xi - avg) ^ 2 */
variance += x; /* Summation */
}
sdev = sqrt((double)variance/(double)stats_count);
printf("standard deviation of iops is %.2f\n", sdev);
}
static void stats_test(int fd, int write_mode, off64_t max_blocks, int stats_count,
char *full_stats_file)
{
struct stats *stats_buf;
char buf[TST_BLK_SIZE] = { 0 };
int i;
stats_buf = malloc(stats_count * sizeof(struct stats));
if (stats_buf == NULL) {
fprintf(stderr, "Cannot allocate stats_buf\n");
exit(1);
}
for (i = 0; i < stats_count; i++) {
gettimeofday(&stats_buf[i].start, NULL);
if (lseek64(fd, (rand() % max_blocks) * TST_BLK_SIZE, SEEK_SET) < 0) {
fprintf(stderr, "lseek64 failed\n");
}
if (write_mode) {
if (write(fd, buf, sizeof(buf)) != sizeof(buf)) {
fprintf(stderr, "Short write\n");
}
} else {
if (read(fd, buf, sizeof(buf)) != sizeof(buf)) {
fprintf(stderr, "Short read\n");
}
}
gettimeofday(&stats_buf[i].end, NULL);
}
print_stats(stats_buf, stats_count, full_stats_file);
}
static void perf_test(int fd, int write_mode, off64_t max_blocks)
{
struct timeval start, end, res;
char buf[TST_BLK_SIZE] = { 0 };
long long iops = 0;
int msecs;
res.tv_sec = 0;
gettimeofday(&start, NULL);
while (res.tv_sec < TEST_LEN) {
if (lseek64(fd, (rand() % max_blocks) * TST_BLK_SIZE, SEEK_SET) < 0) {
fprintf(stderr, "lseek64 failed\n");
}
if (write_mode) {
if (write(fd, buf, sizeof(buf)) != sizeof(buf)) {
fprintf(stderr, "Short write\n");
}
} else {
if (read(fd, buf, sizeof(buf)) != sizeof(buf)) {
fprintf(stderr, "Short read\n");
}
}
iops++;
gettimeofday(&end, NULL);
timersub(&end, &start, &res);
}
close(fd);
/* The close can take a while when in write_mode as buffers are flushed.
* So get the time again. */
gettimeofday(&end, NULL);
timersub(&end, &start, &res);
msecs = (res.tv_sec * 1000) + (res.tv_usec / 1000);
printf("%.0f %dbyte iops/sec\n", (float)iops * 1000 / msecs, TST_BLK_SIZE);
}
int main(int argc, char *argv[])
{
int fd, fd2;
int write_mode = 0;
int o_sync = 0;
int stats_mode = 0;
int stats_count;
char *full_stats_file = NULL;
off64_t max_blocks;
unsigned int seed;
int c;
while ((c = getopt(argc, argv, "+rwos:f:")) != -1) {
switch (c) {
case '?':
default:
usage();
break;
case 'r':
/* Do nothing, read mode is the default */
break;
case 'w':
write_mode = 1;
break;
case 'o':
o_sync = O_SYNC;
break;
case 's':
stats_mode = 1;
stats_count = atoi(optarg);
break;
case 'f':
free(full_stats_file);
full_stats_file = strdup(optarg);
if (full_stats_file == NULL) {
fprintf(stderr, "Cannot get full stats filename\n");
}
break;
}
}
if (o_sync && !write_mode) {
/* Can only specify o_sync in write mode. Probably doesn't matter,
* but clear o_sync if in read mode */
o_sync = 0;
}
if ((argc - optind) != 2) {
usage();
}
/* Size is given in megabytes, so compute the number of TST_BLK_SIZE blocks. */
max_blocks = atoll(argv[optind]) * ((1024*1024) / TST_BLK_SIZE);
if ((fd = open(argv[optind + 1], O_RDWR | o_sync)) < 0) {
fprintf(stderr, "Cannot open block device %s\n", argv[optind + 1]);
exit(1);
}
fd2 = open("/dev/urandom", O_RDONLY);
if (fd2 < 0) {
fprintf(stderr, "Cannot open /dev/urandom\n");
}
if (read(fd2, &seed, sizeof(seed)) != sizeof(seed)) {
fprintf(stderr, "Cannot read /dev/urandom\n");
}
close(fd2);
srand(seed);
if (stats_mode) {
stats_test(fd, write_mode, max_blocks, stats_count, full_stats_file);
} else {
perf_test(fd, write_mode, max_blocks);
}
free(full_stats_file);
exit(0);
}