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 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