sysdeps/unix/sysv/linux/tst-skeleton-thread-affinity.c

   1 /* Generic test for CPU affinity functions, multi-threaded variant.
   2    Copyright (C) 2015-2024 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 /* Before including this file, a test has to declare the helper
  20    getaffinity and setaffinity functions described in
  21    tst-skeleton-affinity.c, which is included below.  */
  22
  23 #include <errno.h>
  24 #include <pthread.h>
  25 #include <stdbool.h>
  26 #include <stdlib.h>
  27 #include <support/xthread.h>
  28 #include <sys/time.h>
  29
  30 struct conf;
  31 static bool early_test (struct conf *);
  32
  33 /* Arbitrary run time for each pass.  */
  34 #define PASS_TIMEOUT 2
  35
  36 /* There are two passes (one with sched_yield, one without), and we
  37    double the timeout to be on the safe side.  */
  38 #define TIMEOUT (2 * PASS_TIMEOUT * 2)
  39
  40 #include "tst-skeleton-affinity.c"
  41
  42 /* 0 if still running, 1 of stopping requested.  */
  43 static int still_running;
  44
  45 /* 0 if no scheduling failures, 1 if failures are encountered.  */
  46 static int failed;
  47
  48 static void *
  49 thread_burn_one_cpu (void *closure)
  50 {
  51   int cpu = (uintptr_t) closure;
  52   while (__atomic_load_n (&still_running, __ATOMIC_RELAXED) == 0)
  53     {
  54       int current = sched_getcpu ();
  55       if (sched_getcpu () != cpu)
  56         {
  57           printf ("error: Pinned thread %d ran on impossible cpu %d\n",
  58                   cpu, current);
  59           __atomic_store_n (&failed, 1, __ATOMIC_RELAXED);
  60           /* Terminate early.  */
  61           __atomic_store_n (&still_running, 1, __ATOMIC_RELAXED);
  62         }
  63     }
  64   return NULL;
  65 }
  66
  67 struct burn_thread
  68 {
  69   pthread_t self;
  70   struct conf *conf;
  71   cpu_set_t *initial_set;
  72   cpu_set_t *seen_set;
  73   int thread;
  74 };
  75
  76 static void *
  77 thread_burn_any_cpu (void *closure)
  78 {
  79   struct burn_thread *param = closure;
  80
  81   /* Schedule this thread around a bit to see if it lands on another
  82      CPU.  Run this for 2 seconds, once with sched_yield, once
  83      without.  */
  84   for (int pass = 1; pass <= 2; ++pass)
  85     {
  86       time_t start = time (NULL);
  87       while (time (NULL) - start <= PASS_TIMEOUT)
  88         {
  89           int cpu = sched_getcpu ();
  90           if (cpu > param->conf->last_cpu
  91               || !CPU_ISSET_S (cpu, CPU_ALLOC_SIZE (param->conf->set_size),
  92                                param->initial_set))
  93             {
  94               printf ("error: Unpinned thread %d ran on impossible CPU %d\n",
  95                       param->thread, cpu);
  96               __atomic_store_n (&failed, 1, __ATOMIC_RELAXED);
  97               return NULL;
  98             }
  99           CPU_SET_S (cpu, CPU_ALLOC_SIZE (param->conf->set_size),
 100                      param->seen_set);
 101           if (pass == 1)
 102             sched_yield ();
 103         }
 104     }
 105   return NULL;
 106 }
 107
 108 static void
 109 stop_and_join_threads (struct conf *conf, cpu_set_t *set,
 110                        pthread_t *pinned_first, pthread_t *pinned_last,
 111                        struct burn_thread *other_first,
 112                        struct burn_thread *other_last)
 113 {
 114   __atomic_store_n (&still_running, 1, __ATOMIC_RELAXED);
 115   for (pthread_t *p = pinned_first; p < pinned_last; ++p)
 116     {
 117       int cpu = p - pinned_first;
 118       if (!CPU_ISSET_S (cpu, CPU_ALLOC_SIZE (conf->set_size), set))
 119         continue;
 120
 121       int ret = pthread_join (*p, NULL);
 122       if (ret != 0)
 123         {
 124           printf ("error: Failed to join thread %d: %s\n", cpu, strerror (ret));
 125           fflush (stdout);
 126           /* Cannot shut down cleanly with threads still running.  */
 127           abort ();
 128         }
 129     }
 130
 131   for (struct burn_thread *p = other_first; p < other_last; ++p)
 132     {
 133       int cpu = p - other_first;
 134       if (!CPU_ISSET_S (cpu, CPU_ALLOC_SIZE (conf->set_size), set))
 135         continue;
 136
 137       int ret = pthread_join (p->self, NULL);
 138       if (ret != 0)
 139         {
 140           printf ("error: Failed to join thread %d: %s\n", cpu, strerror (ret));
 141           fflush (stdout);
 142           /* Cannot shut down cleanly with threads still running.  */
 143           abort ();
 144         }
 145     }
 146 }
 147
 148 /* Tries to check that the initial set of CPUs is complete and that
 149    the main thread will not run on any other threads.  */
 150 static bool
 151 early_test (struct conf *conf)
 152 {
 153   pthread_t *pinned_threads
 154     = calloc (conf->last_cpu + 1, sizeof (*pinned_threads));
 155   struct burn_thread *other_threads
 156     = calloc (conf->last_cpu + 1, sizeof (*other_threads));
 157   cpu_set_t *initial_set = CPU_ALLOC (conf->set_size);
 158   cpu_set_t *scratch_set = CPU_ALLOC (conf->set_size);
 159
 160   if (pinned_threads == NULL || other_threads == NULL
 161       || initial_set == NULL || scratch_set == NULL)
 162     {
 163       puts ("error: Memory allocation failure");
 164       return false;
 165     }
 166   if (getaffinity (CPU_ALLOC_SIZE (conf->set_size), initial_set) < 0)
 167     {
 168       printf ("error: pthread_getaffinity_np failed: %m\n");
 169       return false;
 170     }
 171   for (int cpu = 0; cpu <= conf->last_cpu; ++cpu)
 172     {
 173       if (!CPU_ISSET_S (cpu, CPU_ALLOC_SIZE (conf->set_size), initial_set))
 174         continue;
 175       other_threads[cpu].conf = conf;
 176       other_threads[cpu].initial_set = initial_set;
 177       other_threads[cpu].thread = cpu;
 178       other_threads[cpu].seen_set = CPU_ALLOC (conf->set_size);
 179       if (other_threads[cpu].seen_set == NULL)
 180         {
 181           puts ("error: Memory allocation failure");
 182           return false;
 183         }
 184       CPU_ZERO_S (CPU_ALLOC_SIZE (conf->set_size),
 185                   other_threads[cpu].seen_set);
 186     }
 187
 188   pthread_attr_t attr;
 189   int ret = pthread_attr_init (&attr);
 190   if (ret != 0)
 191     {
 192       printf ("error: pthread_attr_init failed: %s\n", strerror (ret));
 193       return false;
 194     }
 195   support_set_small_thread_stack_size (&attr);
 196
 197   /* Spawn a thread pinned to each available CPU.  */
 198   for (int cpu = 0; cpu <= conf->last_cpu; ++cpu)
 199     {
 200       if (!CPU_ISSET_S (cpu, CPU_ALLOC_SIZE (conf->set_size), initial_set))
 201         continue;
 202       CPU_ZERO_S (CPU_ALLOC_SIZE (conf->set_size), scratch_set);
 203       CPU_SET_S (cpu, CPU_ALLOC_SIZE (conf->set_size), scratch_set);
 204       ret = pthread_attr_setaffinity_np
 205         (&attr, CPU_ALLOC_SIZE (conf->set_size), scratch_set);
 206       if (ret != 0)
 207         {
 208           printf ("error: pthread_attr_setaffinity_np for CPU %d failed: %s\n",
 209                   cpu, strerror (ret));
 210           stop_and_join_threads (conf, initial_set,
 211                                  pinned_threads, pinned_threads + cpu,
 212                                  NULL, NULL);
 213           return false;
 214         }
 215       ret = pthread_create (pinned_threads + cpu, &attr,
 216                             thread_burn_one_cpu, (void *) (uintptr_t) cpu);
 217       if (ret != 0)
 218         {
 219           printf ("error: pthread_create for CPU %d failed: %s\n",
 220                   cpu, strerror (ret));
 221           stop_and_join_threads (conf, initial_set,
 222                                  pinned_threads, pinned_threads + cpu,
 223                                  NULL, NULL);
 224           return false;
 225         }
 226     }
 227
 228   /* Spawn another set of threads running on all CPUs.  */
 229   for (int cpu = 0; cpu <= conf->last_cpu; ++cpu)
 230     {
 231       if (!CPU_ISSET_S (cpu, CPU_ALLOC_SIZE (conf->set_size), initial_set))
 232         continue;
 233       ret = pthread_create (&other_threads[cpu].self,
 234                             support_small_stack_thread_attribute (),
 235                             thread_burn_any_cpu, other_threads + cpu);
 236       if (ret != 0)
 237         {
 238           printf ("error: pthread_create for thread %d failed: %s\n",
 239                   cpu, strerror (ret));
 240           stop_and_join_threads (conf, initial_set,
 241                                  pinned_threads,
 242                                  pinned_threads + conf->last_cpu + 1,
 243                                  other_threads, other_threads + cpu);
 244           return false;
 245         }
 246     }
 247
 248   /* Main thread.  */
 249   struct burn_thread main_thread;
 250   main_thread.conf = conf;
 251   main_thread.initial_set = initial_set;
 252   main_thread.seen_set = scratch_set;
 253   main_thread.thread = -1;
 254   CPU_ZERO_S (CPU_ALLOC_SIZE (conf->set_size), main_thread.seen_set);
 255   thread_burn_any_cpu (&main_thread);
 256   stop_and_join_threads (conf, initial_set,
 257                          pinned_threads,
 258                          pinned_threads + conf->last_cpu + 1,
 259                          other_threads, other_threads + conf->last_cpu + 1);
 260
 261   printf ("info: Main thread ran on %d CPU(s) of %d available CPU(s)\n",
 262           CPU_COUNT_S (CPU_ALLOC_SIZE (conf->set_size), scratch_set),
 263           CPU_COUNT_S (CPU_ALLOC_SIZE (conf->set_size), initial_set));
 264   CPU_ZERO_S (CPU_ALLOC_SIZE (conf->set_size), scratch_set);
 265   for (int cpu = 0; cpu <= conf->last_cpu; ++cpu)
 266     {
 267       if (!CPU_ISSET_S (cpu, CPU_ALLOC_SIZE (conf->set_size), initial_set))
 268         continue;
 269       CPU_OR_S (CPU_ALLOC_SIZE (conf->set_size),
 270                 scratch_set, scratch_set, other_threads[cpu].seen_set);
 271       CPU_FREE (other_threads[cpu].seen_set);
 272     }
 273   printf ("info: Other threads ran on %d CPU(s)\n",
 274           CPU_COUNT_S (CPU_ALLOC_SIZE (conf->set_size), scratch_set));;
 275
 276
 277   pthread_attr_destroy (&attr);
 278   CPU_FREE (scratch_set);
 279   CPU_FREE (initial_set);
 280   free (pinned_threads);
 281   free (other_threads);
 282   return failed == 0;
 283 }