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104 lines
2.7 KiB
C
104 lines
2.7 KiB
C
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/*******************************************************************************
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* The BYTE UNIX Benchmarks - Release 3
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* Module: context1.c SID: 3.3 5/15/91 19:30:18
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*
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*******************************************************************************
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* Bug reports, patches, comments, suggestions should be sent to:
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*
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* Ben Smith, Rick Grehan or Tom Yager
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* ben@bytepb.byte.com rick_g@bytepb.byte.com tyager@bytepb.byte.com
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*
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*******************************************************************************
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* Modification Log:
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* $Header: context1.c,v 3.4 87/06/22 14:22:59 kjmcdonell Beta $
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* August 28, 1990 - changed timing routines--now returns total number of
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* iterations in specified time period
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* October 22, 1997 - code cleanup to remove ANSI C compiler warnings
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* Andy Kahn <kahn@zk3.dec.com>
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*
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******************************************************************************/
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char SCCSid[] = "@(#) @(#)context1.c:3.3 -- 5/15/91 19:30:18";
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/*
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* Context switching via synchronized unbuffered pipe i/o
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*
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <errno.h>
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#include "timeit.c"
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unsigned long iter;
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int stop_timing=0;
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void report()
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{
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fprintf(stderr, "%lu context switches per second.\n", iter);
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stop_timing=1;
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}
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void context_switch_test(int duration)
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{
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unsigned long check;
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int p1[2], p2[2];
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/* set up alarm call */
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iter = 0;
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wake_me(duration, report);
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if (pipe(p1) || pipe(p2)) {
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perror("pipe create failed");
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exit(1);
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}
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if (fork()) { /* parent process */
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/* master, write p1 & read p2 */
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close(p1[0]); close(p2[1]);
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while (!stop_timing) {
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if (write(p1[1], (char *)&iter, sizeof(iter)) != sizeof(iter)) {
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if ((errno != 0) && (errno != EINTR))
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perror("master write failed");
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exit(1);
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}
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if (read(p2[0], (char *)&check, sizeof(check)) != sizeof(check)) {
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if ((errno != 0) && (errno != EINTR))
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perror("master read failed");
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exit(1);
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}
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if (check != iter) {
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fprintf(stderr, "Master sync error: expect %lu, got %lu\n",
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iter, check);
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exit(2);
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}
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iter++;
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}
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}
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else { /* child process */
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unsigned long iter1;
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iter1 = 0;
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/* slave, read p1 & write p2 */
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close(p1[1]); close(p2[0]);
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while (!stop_timing) {
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if (read(p1[0], (char *)&check, sizeof(check)) != sizeof(check)) {
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if ((errno != 0) && (errno != EINTR))
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perror("slave read failed");
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exit(1);
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}
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if (check != iter1) {
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fprintf(stderr, "Slave sync error: expect %lu, got %lu\n",
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iter, check);
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exit(2);
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}
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if (write(p2[1], (char *)&iter1, sizeof(iter1)) != sizeof(check)) {
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if ((errno != 0) && (errno != EINTR))
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perror("slave write failed");
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exit(1);
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}
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iter1++;
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}
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}
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}
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