1 /*
2 * pipe2.c
3 */
4 #include <sys/types.h>
5 #include <sys/wait.h>
6 #include <sys/resource.h>
7 #include "blib.h"
8
9 #define PAGE_SIZE 4096
10 #define PAGE_MASK (PAGE_SIZE - 1)
11
12 int
main(int ac,char ** av)13 main(int ac, char **av)
14 {
15 long long count = 0;
16 long long max;
17 char c;
18 int j;
19 int loops;
20 int bytes;
21 int ppri = 999;
22 int fds[2];
23 char *buf;
24 char *ptr;
25 char *msg = "datarate";
26
27 if (ac == 1) {
28 fprintf(stderr, "%s blocksize[k,m] [pipe_writer_pri] [msg]\n", av[0]);
29 exit(1);
30 }
31 bytes = strtol(av[1], &ptr, 0);
32 if (*ptr == 'k' || *ptr == 'K') {
33 bytes *= 1024;
34 } else if (*ptr == 'm' || *ptr == 'M') {
35 bytes *= 1024 * 1024;
36 } else if (*ptr) {
37 fprintf(stderr, "Illegal numerical suffix: %s\n", ptr);
38 exit(1);
39 }
40 if (bytes <= 0) {
41 fprintf(stderr, "I can't handle %d sized buffers\n", bytes);
42 exit(1);
43 }
44 if (ac >= 3)
45 ppri = strtol(av[2], NULL, 0);
46 if (ac >= 4)
47 msg = av[3];
48
49 buf = mmap(NULL, bytes * 2 + PAGE_SIZE,
50 PROT_READ|PROT_WRITE, MAP_SHARED|MAP_ANON, -1, 0);
51 if (buf == MAP_FAILED) {
52 perror("mmap/buffer");
53 exit(1);
54 }
55
56 bzero(buf, bytes * 2 + PAGE_SIZE);
57
58 printf("tests one-way pipe using direct-write buffer\n");
59 if (pipe(fds)) {
60 perror("pipe");
61 exit(1);
62 }
63 if (fork() == 0) {
64 /*
65 * child process
66 */
67 int n;
68 int i;
69
70 close(fds[0]);
71 buf += (bytes + PAGE_MASK) & ~PAGE_MASK;
72 i = 0;
73 for (;;) {
74 n = read(fds[1], buf + i, bytes - i);
75 if (n <= 0)
76 break;
77 if (n + i == bytes)
78 i = 0;
79 else
80 i += n;
81 }
82 _exit(0);
83 } else {
84 /*
85 * parent process.
86 */
87 if (ppri != 999) {
88 if (setpriority(PRIO_PROCESS, getpid(), ppri) < 0) {
89 perror("setpriority");
90 exit(1);
91 }
92 }
93 close(fds[1]);
94
95 /*
96 * Figure out how many loops it takes for 1 second's worth.
97 */
98 start_timing();
99 for (j = 0; ; ++j) {
100 if (write(fds[0], buf, bytes) != bytes) {
101 perror("write");
102 exit(1);
103 }
104 if ((j & 31) == 0 && stop_timing(0, NULL))
105 break;
106 }
107 loops = j * 2 + 1;
108 loops *= 2;
109 usleep(1000000 / 10);
110 start_timing();
111
112 for (j = loops; j; --j) {
113 if (write(fds[0], buf, bytes) != bytes) {
114 perror("write");
115 exit(1);
116 }
117 }
118 close(fds[0]);
119 while(wait(NULL) >= 0)
120 ;
121 stop_timing(loops, "full duplex pipe / %dK bufs:", bytes / 1024);
122 printf("%s: blkSize %d %5.2f MBytes/sec\n",
123 msg,
124 bytes,
125 (double)loops * bytes * 1000000.0 /
126 (1024.0 * 1024.0 * get_timing()));
127 }
128 return(0);
129 }
130
131