1/* Copyright (C) 2005 Free Software Foundation, Inc. 2 Contributed by Richard Henderson <rth@redhat.com>. 3 4 This file is part of the GNU OpenMP Library (libgomp). 5 6 Libgomp is free software; you can redistribute it and/or modify it 7 under the terms of the GNU Lesser General Public License as published by 8 the Free Software Foundation; either version 2.1 of the License, or 9 (at your option) any later version. 10 11 Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY 12 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 13 FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for 14 more details. 15 16 You should have received a copy of the GNU Lesser General Public License 17 along with libgomp; see the file COPYING.LIB. If not, write to the 18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, 19 MA 02110-1301, USA. */ 20 21/* As a special exception, if you link this library with other files, some 22 of which are compiled with GCC, to produce an executable, this library 23 does not by itself cause the resulting executable to be covered by the 24 GNU General Public License. This exception does not however invalidate 25 any other reasons why the executable file might be covered by the GNU 26 General Public License. */ 27 28/* This file handles the (bare) PARALLEL construct. */ 29 30#include "libgomp.h" 31 32 33/* Determine the number of threads to be launched for a PARALLEL construct. 34 This algorithm is explicitly described in OpenMP 2.5 section 2.4.1. 35 SPECIFIED is a combination of the NUM_THREADS clause and the IF clause. 36 If the IF clause is false, SPECIFIED is forced to 1. When NUM_THREADS 37 is not present, SPECIFIED is 0. */ 38 39unsigned 40gomp_resolve_num_threads (unsigned specified) 41{ 42 /* Early exit for false IF condition or degenerate NUM_THREADS. */ 43 if (specified == 1) 44 return 1; 45 46 /* If this is a nested region, and nested regions are disabled, force 47 this team to use only one thread. */ 48 if (gomp_thread()->ts.team && !gomp_nest_var) 49 return 1; 50 51 /* If NUM_THREADS not specified, use nthreads_var. */ 52 if (specified == 0) 53 specified = gomp_nthreads_var; 54 55 /* If dynamic threads are enabled, bound the number of threads 56 that we launch. */ 57 if (gomp_dyn_var) 58 { 59 unsigned dyn = gomp_dynamic_max_threads (); 60 if (dyn < specified) 61 return dyn; 62 } 63 64 return specified; 65} 66 67void 68GOMP_parallel_start (void (*fn) (void *), void *data, unsigned num_threads) 69{ 70 num_threads = gomp_resolve_num_threads (num_threads); 71 gomp_team_start (fn, data, num_threads, NULL); 72} 73 74void 75GOMP_parallel_end (void) 76{ 77 gomp_team_end (); 78} 79 80 81/* The public OpenMP API for thread and team related inquiries. */ 82 83int 84omp_get_num_threads (void) 85{ 86 struct gomp_team *team = gomp_thread ()->ts.team; 87 return team ? team->nthreads : 1; 88} 89 90/* ??? Does this function need to disregard dyn_var? I don't see 91 how else one could get a useable "maximum". */ 92 93int 94omp_get_max_threads (void) 95{ 96 return gomp_resolve_num_threads (0); 97} 98 99int 100omp_get_thread_num (void) 101{ 102 return gomp_thread ()->ts.team_id; 103} 104 105/* ??? This isn't right. The definition of this function is false if any 106 of the IF clauses for any of the parallels is false. Which is not the 107 same thing as any outer team having more than one thread. */ 108 109int omp_in_parallel (void) 110{ 111 struct gomp_team *team = gomp_thread ()->ts.team; 112 113 while (team) 114 { 115 if (team->nthreads > 1) 116 return true; 117 team = team->prev_ts.team; 118 } 119 120 return false; 121} 122 123ialias (omp_get_num_threads) 124ialias (omp_get_max_threads) 125ialias (omp_get_thread_num) 126ialias (omp_in_parallel) 127