1 /*
2 * Copyright (C) 2010 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 /* A simple test of emmc random read and write performance. When testing write
18 * performance, try it twice, once with O_SYNC compiled in, and once with it commented
19 * out. Without O_SYNC, the close(2) blocks until all the dirty buffers are written
20 * out, but the numbers tend to be higher.
21 */
22
23 #define _LARGEFILE64_SOURCE
24 #include <string.h>
25 #include <stdio.h>
26 #include <sys/types.h>
27 #include <sys/stat.h>
28 #include <fcntl.h>
29 #include <sys/time.h>
30 #include <stdlib.h>
31 #include <unistd.h>
32 #include <math.h>
33
34 #define TST_BLK_SIZE 4096
35 /* Number of seconds to run the test */
36 #define TEST_LEN 10
37
38 struct stats {
39 struct timeval start;
40 struct timeval end;
41 off64_t offset;
42 };
43
usage(void)44 static void usage(void) {
45 fprintf(stderr, "Usage: rand_emmc_perf [ -r | -w ] [-o] [-s count] [-f full_stats_filename] <size_in_mb> <block_dev>\n");
46 exit(1);
47 }
48
print_stats(struct stats * stats_buf,int stats_count,char * full_stats_file)49 static void print_stats(struct stats *stats_buf, int stats_count,
50 char * full_stats_file)
51 {
52 int i;
53 struct timeval t;
54 struct timeval sum = { 0, 0 };
55 struct timeval max = { 0, 0 };
56 long long total_usecs;
57 long long avg_usecs;
58 long long max_usecs;
59 long long variance = 0;;
60 long long x;
61 double sdev;
62 FILE *full_stats = NULL;
63
64 if (full_stats_file) {
65 full_stats = fopen(full_stats_file, "w");
66 if (full_stats == NULL) {
67 fprintf(stderr, "Cannot open full stats output file %s, ignoring\n",
68 full_stats_file);
69 }
70 }
71
72 for (i = 0; i < stats_count; i++) {
73 timersub(&stats_buf[i].end, &stats_buf[i].start, &t);
74 if (timercmp(&t, &max, >)) {
75 max = t;
76 }
77 if (full_stats) {
78 fprintf(full_stats, "%lld\n", (t.tv_sec * 1000000LL) + t.tv_usec);
79 }
80 timeradd(&sum, &t, &sum);
81 }
82
83 if (full_stats) {
84 fclose(full_stats);
85 }
86
87 max_usecs = (max.tv_sec * 1000000LL) + max.tv_usec;
88 total_usecs = (sum.tv_sec * 1000000LL) + sum.tv_usec;
89 avg_usecs = total_usecs / stats_count;
90 printf("average random %d byte iop time = %lld usecs\n",
91 TST_BLK_SIZE, avg_usecs);
92 printf("maximum random %d byte iop time = %lld usecs\n",
93 TST_BLK_SIZE, max_usecs);
94
95 /* Now that we have the average (aka mean) go through the data
96 * again and compute the standard deviation.
97 * The formula is sqrt(sum_1_to_n((Xi - avg)^2)/n)
98 */
99 for (i = 0; i < stats_count; i++) {
100 timersub(&stats_buf[i].end, &stats_buf[i].start, &t); /* Xi */
101 x = (t.tv_sec * 1000000LL) + t.tv_usec; /* Convert to long long */
102 x = x - avg_usecs; /* Xi - avg */
103 x = x * x; /* (Xi - avg) ^ 2 */
104 variance += x; /* Summation */
105 }
106 sdev = sqrt((double)variance/(double)stats_count);
107 printf("standard deviation of iops is %.2f\n", sdev);
108 }
109
stats_test(int fd,int write_mode,off64_t max_blocks,int stats_count,char * full_stats_file)110 static void stats_test(int fd, int write_mode, off64_t max_blocks, int stats_count,
111 char *full_stats_file)
112 {
113 struct stats *stats_buf;
114 char buf[TST_BLK_SIZE] = { 0 };
115 int i;
116
117 stats_buf = malloc(stats_count * sizeof(struct stats));
118 if (stats_buf == NULL) {
119 fprintf(stderr, "Cannot allocate stats_buf\n");
120 exit(1);
121 }
122
123 for (i = 0; i < stats_count; i++) {
124 gettimeofday(&stats_buf[i].start, NULL);
125
126 if (lseek64(fd, (rand() % max_blocks) * TST_BLK_SIZE, SEEK_SET) < 0) {
127 fprintf(stderr, "lseek64 failed\n");
128 }
129
130 if (write_mode) {
131 if (write(fd, buf, sizeof(buf)) != sizeof(buf)) {
132 fprintf(stderr, "Short write\n");
133 }
134 } else {
135 if (read(fd, buf, sizeof(buf)) != sizeof(buf)) {
136 fprintf(stderr, "Short read\n");
137 }
138 }
139
140 gettimeofday(&stats_buf[i].end, NULL);
141 }
142
143 print_stats(stats_buf, stats_count, full_stats_file);
144 }
145
perf_test(int fd,int write_mode,off64_t max_blocks)146 static void perf_test(int fd, int write_mode, off64_t max_blocks)
147 {
148 struct timeval start, end, res;
149 char buf[TST_BLK_SIZE] = { 0 };
150 long long iops = 0;
151 int msecs;
152
153 res.tv_sec = 0;
154 gettimeofday(&start, NULL);
155 while (res.tv_sec < TEST_LEN) {
156 if (lseek64(fd, (rand() % max_blocks) * TST_BLK_SIZE, SEEK_SET) < 0) {
157 fprintf(stderr, "lseek64 failed\n");
158 }
159 if (write_mode) {
160 if (write(fd, buf, sizeof(buf)) != sizeof(buf)) {
161 fprintf(stderr, "Short write\n");
162 }
163 } else {
164 if (read(fd, buf, sizeof(buf)) != sizeof(buf)) {
165 fprintf(stderr, "Short read\n");
166 }
167 }
168 iops++;
169 gettimeofday(&end, NULL);
170 timersub(&end, &start, &res);
171 }
172 close(fd);
173
174 /* The close can take a while when in write_mode as buffers are flushed.
175 * So get the time again. */
176 gettimeofday(&end, NULL);
177 timersub(&end, &start, &res);
178
179 msecs = (res.tv_sec * 1000) + (res.tv_usec / 1000);
180 printf("%.0f %dbyte iops/sec\n", (float)iops * 1000 / msecs, TST_BLK_SIZE);
181 }
182
main(int argc,char * argv[])183 int main(int argc, char *argv[])
184 {
185 int fd, fd2;
186 int write_mode = 0;
187 int o_sync = 0;
188 int stats_mode = 0;
189 int stats_count;
190 char *full_stats_file = NULL;
191 off64_t max_blocks;
192 unsigned int seed;
193 int c;
194
195 while ((c = getopt(argc, argv, "+rwos:f:")) != -1) {
196 switch (c) {
197 case '?':
198 default:
199 usage();
200 break;
201
202 case 'r':
203 /* Do nothing, read mode is the default */
204 break;
205
206 case 'w':
207 write_mode = 1;
208 break;
209
210 case 'o':
211 o_sync = O_SYNC;
212 break;
213
214 case 's':
215 stats_mode = 1;
216 stats_count = atoi(optarg);
217 break;
218
219 case 'f':
220 free(full_stats_file);
221 full_stats_file = strdup(optarg);
222 if (full_stats_file == NULL) {
223 fprintf(stderr, "Cannot get full stats filename\n");
224 }
225 break;
226 }
227 }
228
229 if (o_sync && !write_mode) {
230 /* Can only specify o_sync in write mode. Probably doesn't matter,
231 * but clear o_sync if in read mode */
232 o_sync = 0;
233 }
234
235 if ((argc - optind) != 2) {
236 usage();
237 }
238
239 /* Size is given in megabytes, so compute the number of TST_BLK_SIZE blocks. */
240 max_blocks = atoll(argv[optind]) * ((1024*1024) / TST_BLK_SIZE);
241
242 if ((fd = open(argv[optind + 1], O_RDWR | o_sync)) < 0) {
243 fprintf(stderr, "Cannot open block device %s\n", argv[optind + 1]);
244 exit(1);
245 }
246
247 fd2 = open("/dev/urandom", O_RDONLY);
248 if (fd2 < 0) {
249 fprintf(stderr, "Cannot open /dev/urandom\n");
250 }
251 if (read(fd2, &seed, sizeof(seed)) != sizeof(seed)) {
252 fprintf(stderr, "Cannot read /dev/urandom\n");
253 }
254 close(fd2);
255 srand(seed);
256
257 if (stats_mode) {
258 stats_test(fd, write_mode, max_blocks, stats_count, full_stats_file);
259 } else {
260 perf_test(fd, write_mode, max_blocks);
261 }
262 free(full_stats_file);
263
264 exit(0);
265 }
266
267