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
42static char buffer[1024*1024];
43
44/* Return current time in milli-seconds, as a double */
45static double
46now_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
53void 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
61void 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
78int 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