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