| /* Copyright (C) 2005, 2006 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 system specific routines related to counting |
| online processors and dynamic load balancing. It is expected that |
| a system may well want to write special versions of each of these. |
| |
| The following implementation uses a mix of POSIX and BSD routines. */ |
| |
| #include "libgomp.h" |
| #include <unistd.h> |
| #include <stdlib.h> |
| #ifdef HAVE_GETLOADAVG |
| # ifdef HAVE_SYS_LOADAVG_H |
| # include <sys/loadavg.h> |
| # endif |
| #endif |
| |
| |
| /* At startup, determine the default number of threads. It would seem |
| this should be related to the number of cpus online. */ |
| |
| void |
| gomp_init_num_threads (void) |
| { |
| #ifdef _SC_NPROCESSORS_ONLN |
| gomp_nthreads_var = sysconf (_SC_NPROCESSORS_ONLN); |
| #endif |
| } |
| |
| /* When OMP_DYNAMIC is set, at thread launch determine the number of |
| threads we should spawn for this team. */ |
| /* ??? I have no idea what best practice for this is. Surely some |
| function of the number of processors that are *still* online and |
| the load average. Here I use the number of processors online |
| minus the 15 minute load average. */ |
| |
| unsigned |
| gomp_dynamic_max_threads (void) |
| { |
| unsigned n_onln, loadavg; |
| |
| #ifdef _SC_NPROCESSORS_ONLN |
| n_onln = sysconf (_SC_NPROCESSORS_ONLN); |
| if (n_onln > gomp_nthreads_var) |
| n_onln = gomp_nthreads_var; |
| #else |
| n_onln = gomp_nthreads_var; |
| #endif |
| |
| loadavg = 0; |
| #ifdef HAVE_GETLOADAVG |
| { |
| double dloadavg[3]; |
| if (getloadavg (dloadavg, 3) == 3) |
| { |
| /* Add 0.1 to get a kind of biased rounding. */ |
| loadavg = dloadavg[2] + 0.1; |
| } |
| } |
| #endif |
| |
| if (loadavg >= n_onln) |
| return 1; |
| else |
| return n_onln - loadavg; |
| } |
| |
| int |
| omp_get_num_procs (void) |
| { |
| #ifdef _SC_NPROCESSORS_ONLN |
| return sysconf (_SC_NPROCESSORS_ONLN); |
| #else |
| return gomp_nthreads_var; |
| #endif |
| } |
| |
| ialias (omp_get_num_procs) |