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Diffstat (limited to 'libgomp/work.c')
| -rw-r--r-- | libgomp/work.c | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/libgomp/work.c b/libgomp/work.c new file mode 100644 index 0000000..cd20c9d --- /dev/null +++ b/libgomp/work.c @@ -0,0 +1,223 @@ +/* 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); + } +} |