diff options
Diffstat (limited to 'tools/regression/p1003_1b/fifo.c')
| -rw-r--r-- | tools/regression/p1003_1b/fifo.c | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/tools/regression/p1003_1b/fifo.c b/tools/regression/p1003_1b/fifo.c new file mode 100644 index 000000000000..614781f8d4fb --- /dev/null +++ b/tools/regression/p1003_1b/fifo.c @@ -0,0 +1,227 @@ +/*- + * SPDX-License-Identifier: BSD-4-Clause + * + * Copyright (c) 1996 - 2000 + * HD Associates, Inc. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by HD Associates, Inc + * 4. Neither the name of the author nor the names of any co-contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY HD ASSOCIATES AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL HD ASSOCIATES OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ +#include <sys/types.h> +#include <sys/mman.h> +#include <sys/time.h> +#include <err.h> +#include <errno.h> +#include <fcntl.h> +#include <sched.h> +#include <signal.h> +#include <stdlib.h> +#include <stdio.h> +#include <unistd.h> + +volatile int ticked; +#define CAN_USE_ALARMS + +#ifdef CAN_USE_ALARMS +void tick(int arg) +{ + ticked = 1; +} +#endif + +/* Fifo: Verify that fifo and round-robin scheduling seem to work. + * + * This tests: + * 1. That sched_rr_get_interval seems to work; + * 2. That FIFO scheduling doesn't seeem to be round-robin; + * 3. That round-robin scheduling seems to work. + * + */ +static pid_t child; +static void tidyup(void) +{ + if (child) + kill(child, SIGHUP); +} + +static double +tvsub(const struct timeval *a, const struct timeval *b) +{ + long sdiff; + long udiff; + + sdiff = a->tv_sec - b->tv_sec; + udiff = a->tv_usec - b->tv_usec; + + return (double)(sdiff * 1000000 + udiff) / 1e6; +} + +int fifo(int argc, char *argv[]) +{ + int e = 0; + volatile long *p, pid; + int i; + struct sched_param fifo_param; + struct timespec interval; +#define MAX_RANAT 32 + struct timeval ranat[MAX_RANAT]; + +#ifdef CAN_USE_ALARMS + static struct itimerval itimerval; +#endif + + /* What is the round robin interval? + */ + + if (sched_rr_get_interval(0, &interval) == -1) { + perror("sched_rr_get_interval"); + exit(errno); + } + +#ifdef CAN_USE_ALARMS + signal(SIGALRM, tick); +#endif + + fifo_param.sched_priority = 1; + + p = (long *)mmap(0, sizeof(*p), + PROT_READ|PROT_WRITE, MAP_ANON|MAP_SHARED, -1, 0); + + if (p == (long *)-1) + err(errno, "mmap"); + + *p = 0; + + if (sched_setscheduler(0, SCHED_FIFO, &fifo_param) == -1) + { + perror("sched_setscheduler"); + return -1; + } + + pid = getpid(); + + if ((child = fork()) == 0) + { + /* Child process. Just keep setting the pointer to our + * PID. The parent will kill us when it wants to. + */ + + pid = getpid(); + while (1) + *p = pid; + } + else + { + atexit(tidyup); + *p = pid; + + + ticked = 0; + +#ifdef CAN_USE_ALARMS + /* Set an alarm for 250 times the round-robin interval. + * Then we will verify that a similar priority process + * will not run when we are using the FIFO scheduler. + */ + itimerval.it_value.tv_usec = interval.tv_nsec / (1000 / 250); + + itimerval.it_value.tv_sec = itimerval.it_value.tv_usec / 1000000; + itimerval.it_value.tv_usec %= 1000000; + + + if (setitimer(ITIMER_REAL, &itimerval, 0) == -1) { + perror("setitimer"); + exit(errno); + } +#endif + + + gettimeofday(ranat, 0); + i = 1; + while (!ticked && i < MAX_RANAT) + if (*p == child) { + gettimeofday(ranat + i, 0); + *p = 0; + e = -1; + i++; + } + + if (e) { + int j; + + fprintf(stderr, + "SCHED_FIFO had erroneous context switches:\n"); + for (j = 1; j < i; j++) { + fprintf(stderr, "%d %g\n", j, + tvsub(ranat + j, ranat + j - 1)); + } + return e; + } + + /* Switch to the round robin scheduler and the child + * should run within twice the interval. + */ + if (sched_setscheduler(child, SCHED_RR, &fifo_param) == -1 || + sched_setscheduler(0, SCHED_RR, &fifo_param) == -1) + { + perror("sched_setscheduler"); + return -1; + } + + e = -1; + + ticked = 0; + +#ifdef CAN_USE_ALARMS + + /* Now we do want to see it run. But only set + * the alarm for twice the interval: + */ + itimerval.it_value.tv_usec = interval.tv_nsec / 500; + + if (setitimer(ITIMER_REAL, &itimerval, 0) == -1) { + perror("setitimer"); + exit(errno); + } +#endif + + for (i = 0; !ticked; i++) + if (*p == child) { + e = 0; + break; + } + + if (e) + fprintf(stderr,"Child never ran when it should have.\n"); + } + + exit(e); +} + +#ifdef STANDALONE_TESTS +int main(int argc, char *argv[]) { return fifo(argc, argv); } +#endif |