tools/regression/p1003_1b/sched.c

   1 /*
   2  * Copyright (c) 1996-1999
   3  *      HD Associates, Inc.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by HD Associates, Inc
  16  * 4. Neither the name of the author nor the names of any co-contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY HD ASSOCIATES AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL HD ASSOCIATES OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  * $FreeBSD$
  32  *
  33  */
  34
  35 /* XXX: The spec says that if _POSIX_C_SOURCE is defined then
  36  *      _POSIX_SOURCE is ignored.  However, this is similar to
  37  *      the code in the O'Reilly "POSIX.4" book
  38  */
  39
  40 #define _POSIX_VERSION 199309L
  41 #define _POSIX_SOURCE
  42 #define _POSIX_C_SOURCE 199309L
  43
  44 #include <sys/mman.h>
  45 #include <errno.h>
  46 #include <fcntl.h>
  47 #include <limits.h>
  48 #include <sched.h>
  49 #include <stdio.h>
  50 #define __XSI_VISIBLE 1
  51 #include <stdlib.h>
  52 #undef __XSI_VISIBLE
  53 #include <string.h>
  54 #include <unistd.h>
  55
  56 #include "prutil.h"
  57
  58 static FILE *verbose;
  59
  60 static void
  61 checkpris(int sched)
  62 {
  63         int smin;
  64         int smax;
  65
  66         errno = 0;
  67
  68         if ( (smin = sched_get_priority_min(sched)) == -1 && errno)
  69                 quit("sched_get_priority_min");
  70
  71         if ( (smax = sched_get_priority_max(sched)) == -1 && errno)
  72                 quit("sched_get_priority_max");
  73
  74         if (smax - smin + 1 < 32 || smax < smin) {
  75                 fprintf(stderr, "Illegal priority range for %s: %d to %d\n",
  76                 sched_text(sched), smin, smax);
  77                 exit(-1);
  78         }
  79
  80         if (verbose)
  81                 fprintf(verbose, "%12s: sched_min %2d sched_max %2d\n",
  82                 sched_text(sched), smin, smax);
  83 }
  84
  85 /* Set "try_anyway" to quit if you don't want to go on when
  86  * it doesn't look like something should work.
  87  */
  88 static void try_anyway(const char *s)
  89 {
  90         fputs(s, stderr);
  91         fprintf(stderr, "(trying anyway)\n");
  92         errno = 0;
  93 }
  94
  95 static void q(int line, int code, const char *text)
  96 {
  97         if (code == -1)
  98         {
  99                 fprintf(stderr, "Error at line %d:\n", line);
 100                 perror(text);
 101                 exit(errno);
 102         }
 103 }
 104
 105 int sched(int ac, char *av[])
 106 {
 107         int fifo_schedmin, fifo_schedmax;
 108         int i;
 109         struct sched_param rt_param;
 110         int n_instances = 10;
 111         int sched;
 112
 113         verbose = 0;
 114
 115 #if _POSIX_VERSION < 199309
 116         try_anyway("The _POSIX_VERSION predates P1003.1B\n");
 117 #endif
 118
 119 #if !defined(_POSIX_PRIORITY_SCHEDULING)
 120         try_anyway(
 121         "The environment does not claim to support Posix scheduling.\n");
 122 #endif
 123
 124         /* Is priority scheduling configured?
 125          */
 126         errno = 0;
 127         if (sysconf(_SC_PRIORITY_SCHEDULING) == -1) {
 128                 if (errno != 0) {
 129                         /* This isn't valid - may be a standard violation
 130                          */
 131                         quit("(should not happen) sysconf(_SC_PRIORITY_SCHEDULING)");
 132                 }
 133                 else {
 134                         try_anyway(
 135                         "The environment does not have run-time "
 136                         "support for Posix scheduling.\n");
 137                 }
 138         }
 139
 140         /* Check that the priorities seem reasonable.
 141          */
 142
 143         checkpris(SCHED_FIFO);
 144         checkpris(SCHED_RR);
 145         checkpris(SCHED_OTHER);
 146
 147 /* BSD extensions?
 148  */
 149 #if defined(SCHED_IDLE)
 150         checkpris(SCHED_IDLE);
 151 #endif
 152
 153         fifo_schedmin = sched_get_priority_min(SCHED_FIFO);
 154         fifo_schedmax = sched_get_priority_max(SCHED_FIFO);
 155
 156         /* Make sure we can do some basic schedule switching:
 157          */
 158         {
 159                 struct sched_param orig_param, shouldbe;
 160                 int orig_scheduler = sched_is(__LINE__, &orig_param, -1);
 161
 162                 if (verbose)
 163                         fprintf(verbose,
 164                         "The original scheduler is %s and the priority is %d.\n",
 165                         sched_text(orig_scheduler), orig_param.sched_priority);
 166
 167                 /* Basic check: Try to set current settings:
 168                  */
 169                 q(__LINE__, sched_setscheduler(0, orig_scheduler, &orig_param),
 170                         "sched_setscheduler: Can't set original scheduler");
 171
 172                 rt_param.sched_priority = fifo_schedmin;
 173
 174                 q(__LINE__, sched_setscheduler(0, SCHED_FIFO, &rt_param),
 175                 "sched_setscheduler SCHED_FIFO");
 176
 177                 (void)sched_is(__LINE__, 0, SCHED_FIFO);
 178
 179                 q(__LINE__, sched_getparam(0, &shouldbe), "sched_getparam");
 180
 181                 if (shouldbe.sched_priority != fifo_schedmin)
 182                         quit("sched_setscheduler wrong priority (min)");
 183
 184                 rt_param.sched_priority = fifo_schedmin;
 185
 186                 q(__LINE__, sched_setparam(0, &rt_param),
 187                         "sched_setparam to fifo_schedmin");
 188
 189                 rt_param.sched_priority = fifo_schedmin + 1;
 190
 191                 q(__LINE__, sched_setparam(0, &rt_param),
 192                         "sched_setparam to fifo_schedmin + 1");
 193
 194                 q(__LINE__, sched_getparam(0, &shouldbe),
 195                         "sched_getparam");
 196
 197                 if (shouldbe.sched_priority != fifo_schedmin + 1)
 198                         quit("sched_setscheduler wrong priority (min + 1)");
 199
 200                 q(__LINE__, sched_setscheduler(0, SCHED_RR, &rt_param),
 201                         "sched_setscheduler SCHED_RR");
 202
 203                 (void)sched_is(__LINE__, 0, SCHED_RR);
 204
 205                 q(__LINE__, sched_setscheduler(0, orig_scheduler, &orig_param),
 206                         "sched_setscheduler restoring original scheduler");
 207
 208                 (void)sched_is(__LINE__, 0, orig_scheduler);
 209         }
 210
 211
 212         {
 213                 char nam[] = "P1003_1b_schedXXXXXX";
 214                 int fd;
 215                 pid_t p;
 216                 pid_t *lastrun;
 217
 218                 fd = mkstemp(nam);
 219                 if (fd == -1)
 220                         q(__LINE__, errno, "mkstemp failed");
 221
 222                 (void)unlink(nam);
 223
 224                 p = (pid_t)0;
 225
 226                 write(fd, &p, sizeof(p));
 227
 228                 q(__LINE__,  (int)(lastrun = mmap(0, sizeof(*lastrun), PROT_READ|PROT_WRITE,
 229                 MAP_SHARED, fd, 0)), "mmap");
 230
 231                 /* Set our priority at the highest:
 232                  */
 233                 sched = SCHED_FIFO;
 234                 rt_param.sched_priority = fifo_schedmax;
 235                 q(__LINE__, sched_setscheduler(0, sched, &rt_param),
 236                 "sched_setscheduler sched");
 237
 238                 for (i = 0; i < n_instances; i++)
 239                 {
 240                         pid_t me;
 241
 242                         /* XXX This is completely bogus.  The children never run.
 243                          */
 244                         if ((me = fork()) != 0)
 245                         {
 246                                 /* Parent.
 247                                  */
 248                                 (void)sched_is(__LINE__, 0, sched);
 249
 250                                 /* Lower our priority:
 251                                  */
 252                                 rt_param.sched_priority--;
 253
 254                                 q(__LINE__, sched_setscheduler(0, sched, &rt_param),
 255                                 "sched_setscheduler sched");
 256
 257                                 while (1)
 258                                 {
 259                                         q(__LINE__, sched_getparam(0, &rt_param), "sched_getparam");
 260
 261                                         rt_param.sched_priority--;
 262
 263
 264                                         if (rt_param.sched_priority < fifo_schedmin)
 265                                                 exit(0);
 266
 267                                         *lastrun = me;
 268                                         q(__LINE__, sched_setparam(0, &rt_param), "sched_setparam");
 269
 270                                         if (*lastrun == me)
 271                                         {
 272                                                 /* The child will run twice
 273                                                  * at  the end:
 274                                                  */
 275                                                 if (!me || rt_param.sched_priority != 0)
 276                                                 {
 277                                                         fprintf(stderr,
 278                                                         "ran process %ld twice at priority %d\n",
 279                                                         (long)me, rt_param.sched_priority + 1);
 280                                                         exit(-1);
 281                                                 }
 282                                         }
 283                                 }
 284                         }
 285                 }
 286         }
 287
 288         return 0;
 289 }
 290 #ifdef STANDALONE_TESTS
 291 int main(int argc, char *argv[]) { return sched(argc, argv); }
 292 #endif