1 /*
2 * Copyright (C) 2011 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in
12 * the documentation and/or other materials provided with the
13 * distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 /* This program tries to benchmark stdio operations like fread() and
30 * fwrite() with various chunk sizes. We always read/write from /dev/zero
31 * to ensure that disk speed and caching don't change our results.
32 *
33 * We really do this to measure improvements in the low-level stdio
34 * features.
35 */
36
37 #include <stdio.h>
38 #include <time.h>
39 #include <string.h>
40 #include <errno.h>
41
42 static char buffer[1024*1024];
43
44 /* Return current time in milli-seconds, as a double */
45 static double
now_ms(void)46 now_ms(void)
47 {
48 struct timespec ts;
49 clock_gettime(CLOCK_MONOTONIC, &ts);
50 return ts.tv_sec*1000. + ts.tv_nsec*1e-6;
51 }
52
read_file(FILE * fp,int chunkSize)53 void read_file(FILE* fp, int chunkSize)
54 {
55 int totalSize = sizeof(buffer);
56 for ( ; totalSize > 0; totalSize -= chunkSize) {
57 fread(buffer, 1, chunkSize, fp);
58 }
59 }
60
write_file(FILE * fp,int chunkSize)61 void write_file(FILE* fp, int chunkSize)
62 {
63 int totalSize = sizeof(buffer);
64 for ( ; totalSize > 0; totalSize -= chunkSize) {
65 fwrite(buffer, 1, chunkSize, fp);
66 }
67 }
68
69 #define BENCH(op,...) \
70 do { \
71 double time_ms = now_ms(); \
72 op ; \
73 time_ms = now_ms() - time_ms; \
74 double bandwidth = sizeof(buffer)*1000./1024./time_ms; \
75 printf("bench %-30s %8.2f ms (%.1f KB/s) \n", #op, time_ms, bandwidth ); \
76 } while (0)
77
main(void)78 int main(void)
79 {
80 FILE* fp = fopen("/dev/zero", "rw");
81
82 if (fp == NULL) {
83 fprintf(stderr,"Could not open /dev/zero: %s\n", strerror(errno));
84 return 1;
85 }
86
87 BENCH(read_file(fp,1));
88 BENCH(read_file(fp,2));
89 BENCH(read_file(fp,3));
90 BENCH(read_file(fp,4));
91 BENCH(read_file(fp,8));
92 BENCH(read_file(fp,16));
93 BENCH(read_file(fp,32));
94 BENCH(read_file(fp,64));
95 BENCH(read_file(fp,256));
96 BENCH(read_file(fp,1024));
97 BENCH(read_file(fp,4096));
98 BENCH(read_file(fp,16384));
99 BENCH(read_file(fp,65536));
100
101 BENCH(write_file(fp,1));
102 BENCH(write_file(fp,2));
103 BENCH(write_file(fp,3));
104 BENCH(write_file(fp,4));
105 BENCH(write_file(fp,8));
106 BENCH(write_file(fp,16));
107 BENCH(write_file(fp,32));
108 BENCH(write_file(fp,64));
109 BENCH(write_file(fp,256));
110 BENCH(write_file(fp,1024));
111 BENCH(write_file(fp,4096));
112 BENCH(write_file(fp,16384));
113 BENCH(write_file(fp,65536));
114
115 fclose(fp);
116 return 0;
117 }
118