Листинг А.5. Функция main для измерения полосы пропускания очереди сообщений Posix
//bench/bw_pxmsg.c
1 #include "unpipc.h"
2 #define NAME "bw_pxmsg"
3 void reader(int, mqd_t, int);
4 void writer(int, mqd_t);
5 void *buf;
6 int totalnbytes, xfersize;
7 int
8 main(int argc, char **argv)
9 {
10 int i, nloop, contpipe[2];
11 mqd_t mq;
12 pid_t childpid;
13 struct mq_attr attr;
14 if (argc != 4)
15 err_quit("usage: bw_pxmsg <#loops> <#mbytes> <#bytes/write>");
16 nloop = atoi(argv[1]);
17 totalnbytes = atoi(argv[2]) * 1024 * 1024;
18 xfersize = atoi(argv[3]);
19 buf = Valloc(xfersize);
20 Touch(buf, xfersize);
21 Pipe(contpipe);
22 mq_unlink(Px_ipc_name(NAME)); /* error OK */
23 attr.mq_maxmsg = 4;
24 attr.mq_msgsize = xfersize;
25 mq = Mq_open(Px_ipc_name(NAME), O_RDWR | O_CREAT, FILE_MODE, &attr);
26 if ((childpid = Fork()) == 0) {
27 writer(contpipe[0], mq); /* child */
28 exit(0);
29 }
30 /* 4parent */
31 Start_time();
32 for (i = 0; i < nloop; i++)
33 reader(contpipe[1], mq, totalnbytes);
34 printf("bandwidth: %.3f MB/sec\n",
35 totalnbytes / Stop_time() * nloop);
36 kill(childpid, SIGTERM);
37 Mq_close(mq);
38 Mq_unlink(Px_ipc_name(NAME));
39 exit(0);
40 }