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Diffstat (limited to 'libgomp/config/posix/proc.c')
-rw-r--r-- | libgomp/config/posix/proc.c | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/libgomp/config/posix/proc.c b/libgomp/config/posix/proc.c new file mode 100644 index 00000000000..3f5eb7ddc11 --- /dev/null +++ b/libgomp/config/posix/proc.c @@ -0,0 +1,98 @@ +/* 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 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> + + +/* 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) |