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[/] [openrisc/] [trunk/] [gnu-src/] [gcc-4.5.1/] [libgomp/] [parallel.c] - Rev 473
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/* Copyright (C) 2005, 2007, 2008, 2009 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 General Public License as published by the Free Software Foundation; either version 3, 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 General Public License for more details. Under Section 7 of GPL version 3, you are granted additional permissions described in the GCC Runtime Library Exception, version 3.1, as published by the Free Software Foundation. You should have received a copy of the GNU General Public License and a copy of the GCC Runtime Library Exception along with this program; see the files COPYING3 and COPYING.RUNTIME respectively. If not, see <http://www.gnu.org/licenses/>. */ /* This file handles the (bare) PARALLEL construct. */ #include "libgomp.h" #include <limits.h> /* Determine the number of threads to be launched for a PARALLEL construct. This algorithm is explicitly described in OpenMP 3.0 section 2.4.1. SPECIFIED is a combination of the NUM_THREADS clause and the IF clause. If the IF clause is false, SPECIFIED is forced to 1. When NUM_THREADS is not present, SPECIFIED is 0. */ unsigned gomp_resolve_num_threads (unsigned specified, unsigned count) { struct gomp_thread *thread = gomp_thread(); struct gomp_task_icv *icv; unsigned threads_requested, max_num_threads, num_threads; unsigned long remaining; icv = gomp_icv (false); if (specified == 1) return 1; else if (thread->ts.active_level >= 1 && !icv->nest_var) return 1; else if (thread->ts.active_level >= gomp_max_active_levels_var) return 1; /* If NUM_THREADS not specified, use nthreads_var. */ if (specified == 0) threads_requested = icv->nthreads_var; else threads_requested = specified; max_num_threads = threads_requested; /* If dynamic threads are enabled, bound the number of threads that we launch. */ if (icv->dyn_var) { unsigned dyn = gomp_dynamic_max_threads (); if (dyn < max_num_threads) max_num_threads = dyn; /* Optimization for parallel sections. */ if (count && count < max_num_threads) max_num_threads = count; } /* ULONG_MAX stands for infinity. */ if (__builtin_expect (gomp_thread_limit_var == ULONG_MAX, 1) || max_num_threads == 1) return max_num_threads; #ifdef HAVE_SYNC_BUILTINS do { remaining = gomp_remaining_threads_count; num_threads = max_num_threads; if (num_threads > remaining) num_threads = remaining + 1; } while (__sync_val_compare_and_swap (&gomp_remaining_threads_count, remaining, remaining - num_threads + 1) != remaining); #else gomp_mutex_lock (&gomp_remaining_threads_lock); num_threads = max_num_threads; remaining = gomp_remaining_threads_count; if (num_threads > remaining) num_threads = remaining + 1; gomp_remaining_threads_count -= num_threads - 1; gomp_mutex_unlock (&gomp_remaining_threads_lock); #endif return num_threads; } void GOMP_parallel_start (void (*fn) (void *), void *data, unsigned num_threads) { num_threads = gomp_resolve_num_threads (num_threads, 0); gomp_team_start (fn, data, num_threads, gomp_new_team (num_threads)); } void GOMP_parallel_end (void) { if (__builtin_expect (gomp_thread_limit_var != ULONG_MAX, 0)) { struct gomp_thread *thr = gomp_thread (); struct gomp_team *team = thr->ts.team; if (team && team->nthreads > 1) { #ifdef HAVE_SYNC_BUILTINS __sync_fetch_and_add (&gomp_remaining_threads_count, 1UL - team->nthreads); #else gomp_mutex_lock (&gomp_remaining_threads_lock); gomp_remaining_threads_count -= team->nthreads - 1; #endif } } gomp_team_end (); } /* The public OpenMP API for thread and team related inquiries. */ int omp_get_num_threads (void) { struct gomp_team *team = gomp_thread ()->ts.team; return team ? team->nthreads : 1; } int omp_get_thread_num (void) { return gomp_thread ()->ts.team_id; } /* This wasn't right for OpenMP 2.5. Active region used to be non-zero when the IF clause doesn't evaluate to false, starting with OpenMP 3.0 it is non-zero with more than one thread in the team. */ int omp_in_parallel (void) { return gomp_thread ()->ts.active_level > 0; } int omp_get_level (void) { return gomp_thread ()->ts.level; } int omp_get_ancestor_thread_num (int level) { struct gomp_team_state *ts = &gomp_thread ()->ts; if (level < 0 || level > ts->level) return -1; for (level = ts->level - level; level > 0; --level) ts = &ts->team->prev_ts; return ts->team_id; } int omp_get_team_size (int level) { struct gomp_team_state *ts = &gomp_thread ()->ts; if (level < 0 || level > ts->level) return -1; for (level = ts->level - level; level > 0; --level) ts = &ts->team->prev_ts; if (ts->team == NULL) return 1; else return ts->team->nthreads; } int omp_get_active_level (void) { return gomp_thread ()->ts.active_level; } ialias (omp_get_num_threads) ialias (omp_get_thread_num) ialias (omp_in_parallel) ialias (omp_get_level) ialias (omp_get_ancestor_thread_num) ialias (omp_get_team_size) ialias (omp_get_active_level)
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