libgomp/config/rtems/pool.h

   1 /* Copyright (C) 2015-2016 Free Software Foundation, Inc.
   2    Contributed by Sebastian Huber <sebastian.huber@embedded-brains.de>.
   3
   4    This file is part of the GNU Offloading and Multi Processing Library
   5    (libgomp).
   6
   7    Libgomp is free software; you can redistribute it and/or modify it
   8    under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3, or (at your option)
  10    any later version.
  11
  12    Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY
  13    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  14    FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  15    more details.
  16
  17    Under Section 7 of GPL version 3, you are granted additional
  18    permissions described in the GCC Runtime Library Exception, version
  19    3.1, as published by the Free Software Foundation.
  20
  21    You should have received a copy of the GNU General Public License and
  22    a copy of the GCC Runtime Library Exception along with this program;
  23    see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24    <http://www.gnu.org/licenses/>.  */
  25
  26 /* This is the RTEMS implementation of the thread pool management
  27    for libgomp.  This type is private to the library.  */
  28
  29 #ifndef GOMP_POOL_H
  30 #define GOMP_POOL_H 1
  31
  32 #include "libgomp.h"
  33 #include <sys/lock.h>
  34 #include <string.h>
  35
  36 /* For each scheduler instance there may be a thread pool reservoir
  37    to limit the number of thread pools used by the OpenMP master threads of this
  38    scheduler instance.  The reservoirs are configured via the
  39    GOMP_RTEMS_THREAD_POOLS environment variable.  */
  40 struct gomp_thread_pool_reservoir {
  41   gomp_sem_t available;
  42   pthread_spinlock_t lock;
  43   size_t index;
  44   int priority;
  45   struct gomp_thread_pool *pools[];
  46 };
  47
  48 struct gomp_tls_rtems_data {
  49   struct gomp_thread_pool_reservoir *thread_pool_reservoir;
  50 };
  51
  52 extern struct gomp_thread_pool_reservoir **gomp_thread_pool_reservoirs;
  53
  54 extern __thread struct gomp_tls_rtems_data gomp_tls_rtems_data;
  55
  56 static inline struct gomp_thread_pool_reservoir *
  57 gomp_get_thread_pool_reservoir (void)
  58 {
  59   struct gomp_thread_pool_reservoir *res =
  60     gomp_tls_rtems_data.thread_pool_reservoir;
  61
  62   if (res == NULL && gomp_thread_pool_reservoirs != NULL)
  63     {
  64       struct gomp_thread *thr = gomp_thread ();
  65       thr->thread_pool = gomp_malloc_cleared (sizeof (*thr->thread_pool));
  66       res = gomp_thread_pool_reservoirs[_Sched_Index ()];
  67       gomp_tls_rtems_data.thread_pool_reservoir = res;
  68     }
  69
  70   return res;
  71 }
  72
  73 static inline struct gomp_thread_pool *
  74 gomp_get_own_thread_pool (struct gomp_thread *thr, unsigned nthreads)
  75 {
  76   struct gomp_thread_pool *pool = thr->thread_pool;
  77   if (__builtin_expect (pool == NULL, 0))
  78     {
  79       pool = gomp_malloc_cleared (sizeof (*pool));
  80       pool->threads_busy = nthreads;
  81       thr->thread_pool = pool;
  82     }
  83   return pool;
  84 }
  85
  86 static inline struct gomp_thread_pool *
  87 gomp_get_thread_pool (struct gomp_thread *thr, unsigned nthreads)
  88 {
  89   struct gomp_thread_pool *pool;
  90   struct gomp_thread_pool_reservoir *res;
  91
  92   if (__builtin_expect (thr->thread_pool == NULL, 0))
  93     pthread_setspecific (gomp_thread_destructor, thr);
  94
  95   res = gomp_get_thread_pool_reservoir ();
  96   if (res != NULL)
  97     {
  98       gomp_sem_wait (&res->available);
  99       pthread_spin_lock (&res->lock);
 100       pool = res->pools[--res->index];
 101       pthread_spin_unlock (&res->lock);
 102       pool->threads_busy = nthreads;
 103       thr->thread_pool = pool;
 104     }
 105   else
 106     pool = gomp_get_own_thread_pool (thr, nthreads);
 107
 108   return pool;
 109 }
 110
 111 static inline void
 112 gomp_release_thread_pool (struct gomp_thread_pool *pool)
 113 {
 114   struct gomp_thread_pool_reservoir *res =
 115     gomp_tls_rtems_data.thread_pool_reservoir;
 116   if (res != NULL)
 117     {
 118       pthread_spin_lock (&res->lock);
 119       res->pools[res->index++] = pool;
 120       pthread_spin_unlock (&res->lock);
 121       gomp_sem_post (&res->available);
 122     }
 123 }
 124
 125 static inline pthread_attr_t *
 126 gomp_adjust_thread_attr (pthread_attr_t *attr, pthread_attr_t *mutable_attr)
 127 {
 128   struct gomp_thread_pool_reservoir *res = gomp_get_thread_pool_reservoir ();
 129   if (res != NULL && res->priority > 0)
 130     {
 131       struct sched_param param;
 132       int err;
 133       if (attr != mutable_attr)
 134         {
 135           attr = mutable_attr;
 136           pthread_attr_init (attr);
 137         }
 138       memset (&param, 0, sizeof (param));
 139       param.sched_priority = res->priority;
 140       err = pthread_attr_setschedparam (attr, &param);
 141       if (err != 0)
 142         gomp_fatal ("Thread attribute set scheduler parameters failed: %s", strerror (err));
 143       err = pthread_attr_setschedpolicy (attr, SCHED_FIFO);
 144       if (err != 0)
 145         gomp_fatal ("Thread attribute set scheduler policy failed: %s", strerror (err));
 146       err = pthread_attr_setinheritsched (attr, PTHREAD_EXPLICIT_SCHED);
 147       if (err != 0)
 148         gomp_fatal ("Thread attribute set explicit scheduler failed: %s", strerror (err));
 149     }
 150   return attr;
 151 }
 152
 153 #endif /* GOMP_POOL_H */