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/*
* 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.
*/
#include <string.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/time.h>
#include <stdlib.h>
#define TST_BLK_SIZE 4096
/* Number of seconds to run the test */
#define TEST_LEN 10
static void usage(void) {
fprintf(stderr, "Usage: rand_emmc_perf [ -r | -w ] [-o] <size_in_mb> <block_dev>\n");
exit(1);
}
int main(int argc, char *argv[])
{
long max_blocks;
int fd, fd2, write_mode = 0, iops = 0;
struct timeval start, end, res;
unsigned int seed;
char buf[TST_BLK_SIZE] = { 0 };
int c;
int o_sync = 0;
while ((c = getopt(argc, argv, "+rwo")) != -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;
}
}
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 = atol(argv[2]) * ((1024*1024) / TST_BLK_SIZE);
if ((fd = open(argv[3], O_RDWR | o_sync)) < 0) {
fprintf(stderr, "Cannot open block device %s\n", argv[2]);
exit(1);
}
fd2 = open("/dev/urandom\n", 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);
res.tv_sec = 0;
gettimeofday(&start, 0);
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, 0);
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, 0);
timersub(&end, &start, &res);
printf("%d iops/sec\n", iops / (int) res.tv_sec);
exit(0);
}
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