| /* Copyright (C) 2005 Free Software Foundation, Inc. |
| Contributed by Richard Henderson <rth@redhat.com>. |
| |
| This file is part of the GNU OpenMP Library (libgomp). |
| |
| Libgomp is free software; you can redistribute it and/or modify it |
| under the terms of the GNU Lesser General Public License as published by |
| the Free Software Foundation; either version 2.1 of the License, or |
| (at your option) any later version. |
| |
| Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY |
| WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS |
| FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for |
| more details. |
| |
| You should have received a copy of the GNU Lesser General Public License |
| along with libgomp; see the file COPYING.LIB. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, |
| MA 02110-1301, USA. */ |
| |
| /* As a special exception, if you link this library with other files, some |
| of which are compiled with GCC, to produce an executable, this library |
| does not by itself cause the resulting executable to be covered by the |
| GNU General Public License. This exception does not however invalidate |
| any other reasons why the executable file might be covered by the GNU |
| General Public License. */ |
| |
| /* This file contains routines to manage the work-share queue for a team |
| of threads. */ |
| |
| #include "libgomp.h" |
| #include <stdlib.h> |
| #include <string.h> |
| |
| |
| /* Create a new work share structure. */ |
| |
| struct gomp_work_share * |
| gomp_new_work_share (bool ordered, unsigned nthreads) |
| { |
| struct gomp_work_share *ws; |
| size_t size; |
| |
| size = sizeof (*ws); |
| if (ordered) |
| size += nthreads * sizeof (ws->ordered_team_ids[0]); |
| |
| ws = gomp_malloc_cleared (size); |
| gomp_mutex_init (&ws->lock); |
| ws->ordered_owner = -1; |
| |
| return ws; |
| } |
| |
| |
| /* Free a work share structure. */ |
| |
| static void |
| free_work_share (struct gomp_work_share *ws) |
| { |
| gomp_mutex_destroy (&ws->lock); |
| free (ws); |
| } |
| |
| |
| /* The current thread is ready to begin the next work sharing construct. |
| In all cases, thr->ts.work_share is updated to point to the new |
| structure. In all cases the work_share lock is locked. Return true |
| if this was the first thread to reach this point. */ |
| |
| bool |
| gomp_work_share_start (bool ordered) |
| { |
| struct gomp_thread *thr = gomp_thread (); |
| struct gomp_team *team = thr->ts.team; |
| struct gomp_work_share *ws; |
| unsigned ws_index, ws_gen; |
| |
| /* Work sharing constructs can be orphaned. */ |
| if (team == NULL) |
| { |
| ws = gomp_new_work_share (ordered, 1); |
| thr->ts.work_share = ws; |
| thr->ts.static_trip = 0; |
| gomp_mutex_lock (&ws->lock); |
| return true; |
| } |
| |
| gomp_mutex_lock (&team->work_share_lock); |
| |
| /* This thread is beginning its next generation. */ |
| ws_gen = ++thr->ts.work_share_generation; |
| |
| /* If this next generation is not newer than any other generation in |
| the team, then simply reference the existing construct. */ |
| if (ws_gen - team->oldest_live_gen < team->num_live_gen) |
| { |
| ws_index = ws_gen & team->generation_mask; |
| ws = team->work_shares[ws_index]; |
| thr->ts.work_share = ws; |
| thr->ts.static_trip = 0; |
| |
| gomp_mutex_lock (&ws->lock); |
| gomp_mutex_unlock (&team->work_share_lock); |
| |
| return false; |
| } |
| |
| /* Resize the work shares queue if we've run out of space. */ |
| if (team->num_live_gen++ == team->generation_mask) |
| { |
| team->work_shares = gomp_realloc (team->work_shares, |
| 2 * team->num_live_gen |
| * sizeof (*team->work_shares)); |
| |
| /* Unless oldest_live_gen is zero, the sequence of live elements |
| wraps around the end of the array. If we do nothing, we break |
| lookup of the existing elements. Fix that by unwrapping the |
| data from the front to the end. */ |
| if (team->oldest_live_gen > 0) |
| memcpy (team->work_shares + team->num_live_gen, |
| team->work_shares, |
| (team->oldest_live_gen & team->generation_mask) |
| * sizeof (*team->work_shares)); |
| |
| team->generation_mask = team->generation_mask * 2 + 1; |
| } |
| |
| ws_index = ws_gen & team->generation_mask; |
| ws = gomp_new_work_share (ordered, team->nthreads); |
| thr->ts.work_share = ws; |
| thr->ts.static_trip = 0; |
| team->work_shares[ws_index] = ws; |
| |
| gomp_mutex_lock (&ws->lock); |
| gomp_mutex_unlock (&team->work_share_lock); |
| |
| return true; |
| } |
| |
| |
| /* The current thread is done with its current work sharing construct. |
| This version does imply a barrier at the end of the work-share. */ |
| |
| void |
| gomp_work_share_end (void) |
| { |
| struct gomp_thread *thr = gomp_thread (); |
| struct gomp_team *team = thr->ts.team; |
| struct gomp_work_share *ws = thr->ts.work_share; |
| bool last; |
| |
| thr->ts.work_share = NULL; |
| |
| /* Work sharing constructs can be orphaned. */ |
| if (team == NULL) |
| { |
| free_work_share (ws); |
| return; |
| } |
| |
| last = gomp_barrier_wait_start (&team->barrier); |
| |
| if (last) |
| { |
| unsigned ws_index; |
| |
| ws_index = thr->ts.work_share_generation & team->generation_mask; |
| team->work_shares[ws_index] = NULL; |
| team->oldest_live_gen++; |
| team->num_live_gen = 0; |
| |
| free_work_share (ws); |
| } |
| |
| gomp_barrier_wait_end (&team->barrier, last); |
| } |
| |
| |
| /* The current thread is done with its current work sharing construct. |
| This version does NOT imply a barrier at the end of the work-share. */ |
| |
| void |
| gomp_work_share_end_nowait (void) |
| { |
| struct gomp_thread *thr = gomp_thread (); |
| struct gomp_team *team = thr->ts.team; |
| struct gomp_work_share *ws = thr->ts.work_share; |
| unsigned completed; |
| |
| thr->ts.work_share = NULL; |
| |
| /* Work sharing constructs can be orphaned. */ |
| if (team == NULL) |
| { |
| free_work_share (ws); |
| return; |
| } |
| |
| #ifdef HAVE_SYNC_BUILTINS |
| completed = __sync_add_and_fetch (&ws->threads_completed, 1); |
| #else |
| gomp_mutex_lock (&ws->lock); |
| completed = ++ws->threads_completed; |
| gomp_mutex_unlock (&ws->lock); |
| #endif |
| |
| if (completed == team->nthreads) |
| { |
| unsigned ws_index; |
| |
| gomp_mutex_lock (&team->work_share_lock); |
| |
| ws_index = thr->ts.work_share_generation & team->generation_mask; |
| team->work_shares[ws_index] = NULL; |
| team->oldest_live_gen++; |
| team->num_live_gen--; |
| |
| gomp_mutex_unlock (&team->work_share_lock); |
| |
| free_work_share (ws); |
| } |
| } |