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   gomp_mutex_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
  91   if (__builtin_expect (thr->thread_pool == NULL, 0))
  92     pthread_setspecific (gomp_thread_destructor, thr);
  93
  94   if (nthreads != 1)
  95     {
  96       struct gomp_thread_pool_reservoir *res =
  97         gomp_get_thread_pool_reservoir ();
  98       if (res != NULL)
  99         {
 100           gomp_sem_wait (&res->available);
 101           gomp_mutex_lock (&res->lock);
 102           pool = res->pools[--res->index];
 103           gomp_mutex_unlock (&res->lock);
 104           pool->threads_busy = nthreads;
 105           thr->thread_pool = pool;
 106         }
 107       else
 108         pool = gomp_get_own_thread_pool (thr, nthreads);
 109     }
 110   else
 111     pool = NULL;
 112   return pool;
 113 }
 114
 115 static inline void
 116 gomp_release_thread_pool (struct gomp_thread_pool *pool)
 117 {
 118   struct gomp_thread_pool_reservoir *res =
 119     gomp_tls_rtems_data.thread_pool_reservoir;
 120   if (res != NULL)
 121     {
 122       gomp_mutex_lock (&res->lock);
 123       res->pools[res->index++] = pool;
 124       gomp_mutex_unlock (&res->lock);
 125       gomp_sem_post (&res->available);
 126     }
 127 }
 128
 129 static inline pthread_attr_t *
 130 gomp_adjust_thread_attr (pthread_attr_t *attr, pthread_attr_t *mutable_attr)
 131 {
 132   struct gomp_thread_pool_reservoir *res = gomp_get_thread_pool_reservoir ();
 133   if (res != NULL && res->priority > 0)
 134     {
 135       struct sched_param param;
 136       int err;
 137       if (attr != mutable_attr)
 138         {
 139           attr = mutable_attr;
 140           pthread_attr_init (attr);
 141         }
 142       memset (&param, 0, sizeof (param));
 143       param.sched_priority = res->priority;
 144       err = pthread_attr_setschedparam (attr, &param);
 145       if (err != 0)
 146         gomp_fatal ("Thread attribute set scheduler parameters failed: %s", strerror (err));
 147       err = pthread_attr_setschedpolicy (attr, SCHED_FIFO);
 148       if (err != 0)
 149         gomp_fatal ("Thread attribute set scheduler policy failed: %s", strerror (err));
 150       err = pthread_attr_setinheritsched (attr, PTHREAD_EXPLICIT_SCHED);
 151       if (err != 0)
 152         gomp_fatal ("Thread attribute set explicit scheduler failed: %s", strerror (err));
 153     }
 154   return attr;
 155 }
 156
 157 #endif /* GOMP_POOL_H */