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0f00f2c3 LC |
1 | /* Detect the number of processors. |
2 | ||
5e69ceb7 | 3 | Copyright (C) 2009-2014 Free Software Foundation, Inc. |
0f00f2c3 LC |
4 | |
5 | This program is free software; you can redistribute it and/or modify | |
6 | it under the terms of the GNU Lesser General Public License as published by | |
7 | the Free Software Foundation; either version 2, or (at your option) | |
8 | any later version. | |
9 | ||
10 | This program is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | GNU Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public License | |
005de2e8 | 16 | along with this program; if not, see <http://www.gnu.org/licenses/>. */ |
0f00f2c3 LC |
17 | |
18 | /* Written by Glen Lenker and Bruno Haible. */ | |
19 | ||
20 | #include <config.h> | |
21 | #include "nproc.h" | |
22 | ||
23 | #include <stdlib.h> | |
24 | #include <unistd.h> | |
25 | ||
26 | #if HAVE_PTHREAD_GETAFFINITY_NP && 0 | |
27 | # include <pthread.h> | |
28 | # include <sched.h> | |
29 | #endif | |
30 | #if HAVE_SCHED_GETAFFINITY_LIKE_GLIBC || HAVE_SCHED_GETAFFINITY_NP | |
31 | # include <sched.h> | |
32 | #endif | |
33 | ||
34 | #include <sys/types.h> | |
35 | ||
36 | #if HAVE_SYS_PSTAT_H | |
37 | # include <sys/pstat.h> | |
38 | #endif | |
39 | ||
40 | #if HAVE_SYS_SYSMP_H | |
41 | # include <sys/sysmp.h> | |
42 | #endif | |
43 | ||
44 | #if HAVE_SYS_PARAM_H | |
45 | # include <sys/param.h> | |
46 | #endif | |
47 | ||
48 | #if HAVE_SYS_SYSCTL_H | |
49 | # include <sys/sysctl.h> | |
50 | #endif | |
51 | ||
52 | #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__ | |
53 | # define WIN32_LEAN_AND_MEAN | |
54 | # include <windows.h> | |
55 | #endif | |
56 | ||
57 | #include "c-ctype.h" | |
58 | ||
59 | #define ARRAY_SIZE(a) (sizeof (a) / sizeof ((a)[0])) | |
60 | ||
61 | /* Return the number of processors available to the current process, based | |
62 | on a modern system call that returns the "affinity" between the current | |
63 | process and each CPU. Return 0 if unknown or if such a system call does | |
64 | not exist. */ | |
65 | static unsigned long | |
66 | num_processors_via_affinity_mask (void) | |
67 | { | |
68 | /* glibc >= 2.3.3 with NPTL and NetBSD 5 have pthread_getaffinity_np, | |
69 | but with different APIs. Also it requires linking with -lpthread. | |
70 | Therefore this code is not enabled. | |
71 | glibc >= 2.3.4 has sched_getaffinity whereas NetBSD 5 has | |
72 | sched_getaffinity_np. */ | |
73 | #if HAVE_PTHREAD_GETAFFINITY_NP && defined __GLIBC__ && 0 | |
74 | { | |
75 | cpu_set_t set; | |
76 | ||
77 | if (pthread_getaffinity_np (pthread_self (), sizeof (set), &set) == 0) | |
78 | { | |
79 | unsigned long count; | |
80 | ||
81 | # ifdef CPU_COUNT | |
82 | /* glibc >= 2.6 has the CPU_COUNT macro. */ | |
83 | count = CPU_COUNT (&set); | |
84 | # else | |
85 | size_t i; | |
86 | ||
87 | count = 0; | |
88 | for (i = 0; i < CPU_SETSIZE; i++) | |
89 | if (CPU_ISSET (i, &set)) | |
90 | count++; | |
91 | # endif | |
92 | if (count > 0) | |
93 | return count; | |
94 | } | |
95 | } | |
96 | #elif HAVE_PTHREAD_GETAFFINITY_NP && defined __NetBSD__ && 0 | |
97 | { | |
98 | cpuset_t *set; | |
99 | ||
100 | set = cpuset_create (); | |
101 | if (set != NULL) | |
102 | { | |
103 | unsigned long count = 0; | |
104 | ||
105 | if (pthread_getaffinity_np (pthread_self (), cpuset_size (set), set) | |
106 | == 0) | |
107 | { | |
108 | cpuid_t i; | |
109 | ||
110 | for (i = 0;; i++) | |
111 | { | |
112 | int ret = cpuset_isset (i, set); | |
113 | if (ret < 0) | |
114 | break; | |
115 | if (ret > 0) | |
116 | count++; | |
117 | } | |
118 | } | |
119 | cpuset_destroy (set); | |
120 | if (count > 0) | |
121 | return count; | |
122 | } | |
123 | } | |
124 | #elif HAVE_SCHED_GETAFFINITY_LIKE_GLIBC /* glibc >= 2.3.4 */ | |
125 | { | |
126 | cpu_set_t set; | |
127 | ||
128 | if (sched_getaffinity (0, sizeof (set), &set) == 0) | |
129 | { | |
130 | unsigned long count; | |
131 | ||
132 | # ifdef CPU_COUNT | |
133 | /* glibc >= 2.6 has the CPU_COUNT macro. */ | |
134 | count = CPU_COUNT (&set); | |
135 | # else | |
136 | size_t i; | |
137 | ||
138 | count = 0; | |
139 | for (i = 0; i < CPU_SETSIZE; i++) | |
140 | if (CPU_ISSET (i, &set)) | |
141 | count++; | |
142 | # endif | |
143 | if (count > 0) | |
144 | return count; | |
145 | } | |
146 | } | |
147 | #elif HAVE_SCHED_GETAFFINITY_NP /* NetBSD >= 5 */ | |
148 | { | |
149 | cpuset_t *set; | |
150 | ||
151 | set = cpuset_create (); | |
152 | if (set != NULL) | |
153 | { | |
154 | unsigned long count = 0; | |
155 | ||
156 | if (sched_getaffinity_np (getpid (), cpuset_size (set), set) == 0) | |
157 | { | |
158 | cpuid_t i; | |
159 | ||
160 | for (i = 0;; i++) | |
161 | { | |
162 | int ret = cpuset_isset (i, set); | |
163 | if (ret < 0) | |
164 | break; | |
165 | if (ret > 0) | |
166 | count++; | |
167 | } | |
168 | } | |
169 | cpuset_destroy (set); | |
170 | if (count > 0) | |
171 | return count; | |
172 | } | |
173 | } | |
174 | #endif | |
175 | ||
176 | #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__ | |
177 | { /* This works on native Windows platforms. */ | |
178 | DWORD_PTR process_mask; | |
179 | DWORD_PTR system_mask; | |
180 | ||
181 | if (GetProcessAffinityMask (GetCurrentProcess (), | |
182 | &process_mask, &system_mask)) | |
183 | { | |
184 | DWORD_PTR mask = process_mask; | |
185 | unsigned long count = 0; | |
186 | ||
187 | for (; mask != 0; mask = mask >> 1) | |
188 | if (mask & 1) | |
189 | count++; | |
190 | if (count > 0) | |
191 | return count; | |
192 | } | |
193 | } | |
194 | #endif | |
195 | ||
196 | return 0; | |
197 | } | |
198 | ||
199 | unsigned long int | |
200 | num_processors (enum nproc_query query) | |
201 | { | |
202 | if (query == NPROC_CURRENT_OVERRIDABLE) | |
203 | { | |
204 | /* Test the environment variable OMP_NUM_THREADS, recognized also by all | |
205 | programs that are based on OpenMP. The OpenMP spec says that the | |
206 | value assigned to the environment variable "may have leading and | |
207 | trailing white space". */ | |
208 | const char *envvalue = getenv ("OMP_NUM_THREADS"); | |
209 | ||
210 | if (envvalue != NULL) | |
211 | { | |
212 | while (*envvalue != '\0' && c_isspace (*envvalue)) | |
213 | envvalue++; | |
214 | /* Convert it from decimal to 'unsigned long'. */ | |
215 | if (c_isdigit (*envvalue)) | |
216 | { | |
217 | char *endptr = NULL; | |
218 | unsigned long int value = strtoul (envvalue, &endptr, 10); | |
219 | ||
220 | if (endptr != NULL) | |
221 | { | |
222 | while (*endptr != '\0' && c_isspace (*endptr)) | |
223 | endptr++; | |
224 | if (*endptr == '\0') | |
225 | return (value > 0 ? value : 1); | |
226 | } | |
227 | } | |
228 | } | |
229 | ||
230 | query = NPROC_CURRENT; | |
231 | } | |
232 | /* Here query is one of NPROC_ALL, NPROC_CURRENT. */ | |
233 | ||
234 | /* On systems with a modern affinity mask system call, we have | |
235 | sysconf (_SC_NPROCESSORS_CONF) | |
236 | >= sysconf (_SC_NPROCESSORS_ONLN) | |
237 | >= num_processors_via_affinity_mask () | |
238 | The first number is the number of CPUs configured in the system. | |
239 | The second number is the number of CPUs available to the scheduler. | |
240 | The third number is the number of CPUs available to the current process. | |
241 | ||
242 | Note! On Linux systems with glibc, the first and second number come from | |
243 | the /sys and /proc file systems (see | |
244 | glibc/sysdeps/unix/sysv/linux/getsysstats.c). | |
245 | In some situations these file systems are not mounted, and the sysconf | |
246 | call returns 1, which does not reflect the reality. */ | |
247 | ||
248 | if (query == NPROC_CURRENT) | |
249 | { | |
250 | /* Try the modern affinity mask system call. */ | |
251 | { | |
252 | unsigned long nprocs = num_processors_via_affinity_mask (); | |
253 | ||
254 | if (nprocs > 0) | |
255 | return nprocs; | |
256 | } | |
257 | ||
258 | #if defined _SC_NPROCESSORS_ONLN | |
005de2e8 | 259 | { /* This works on glibc, Mac OS X 10.5, FreeBSD, AIX, OSF/1, Solaris, |
0f00f2c3 LC |
260 | Cygwin, Haiku. */ |
261 | long int nprocs = sysconf (_SC_NPROCESSORS_ONLN); | |
262 | if (nprocs > 0) | |
263 | return nprocs; | |
264 | } | |
265 | #endif | |
266 | } | |
267 | else /* query == NPROC_ALL */ | |
268 | { | |
269 | #if defined _SC_NPROCESSORS_CONF | |
005de2e8 | 270 | { /* This works on glibc, Mac OS X 10.5, FreeBSD, AIX, OSF/1, Solaris, |
0f00f2c3 LC |
271 | Cygwin, Haiku. */ |
272 | long int nprocs = sysconf (_SC_NPROCESSORS_CONF); | |
273 | ||
274 | # if __GLIBC__ >= 2 && defined __linux__ | |
275 | /* On Linux systems with glibc, this information comes from the /sys and | |
276 | /proc file systems (see glibc/sysdeps/unix/sysv/linux/getsysstats.c). | |
277 | In some situations these file systems are not mounted, and the | |
278 | sysconf call returns 1. But we wish to guarantee that | |
279 | num_processors (NPROC_ALL) >= num_processors (NPROC_CURRENT). */ | |
280 | if (nprocs == 1) | |
281 | { | |
282 | unsigned long nprocs_current = num_processors_via_affinity_mask (); | |
283 | ||
284 | if (nprocs_current > 0) | |
285 | nprocs = nprocs_current; | |
286 | } | |
287 | # endif | |
288 | ||
289 | if (nprocs > 0) | |
290 | return nprocs; | |
291 | } | |
292 | #endif | |
293 | } | |
294 | ||
295 | #if HAVE_PSTAT_GETDYNAMIC | |
296 | { /* This works on HP-UX. */ | |
297 | struct pst_dynamic psd; | |
298 | if (pstat_getdynamic (&psd, sizeof psd, 1, 0) >= 0) | |
299 | { | |
300 | /* The field psd_proc_cnt contains the number of active processors. | |
301 | In newer releases of HP-UX 11, the field psd_max_proc_cnt includes | |
302 | deactivated processors. */ | |
303 | if (query == NPROC_CURRENT) | |
304 | { | |
305 | if (psd.psd_proc_cnt > 0) | |
306 | return psd.psd_proc_cnt; | |
307 | } | |
308 | else | |
309 | { | |
310 | if (psd.psd_max_proc_cnt > 0) | |
311 | return psd.psd_max_proc_cnt; | |
312 | } | |
313 | } | |
314 | } | |
315 | #endif | |
316 | ||
317 | #if HAVE_SYSMP && defined MP_NAPROCS && defined MP_NPROCS | |
318 | { /* This works on IRIX. */ | |
319 | /* MP_NPROCS yields the number of installed processors. | |
320 | MP_NAPROCS yields the number of processors available to unprivileged | |
321 | processes. */ | |
322 | int nprocs = | |
323 | sysmp (query == NPROC_CURRENT && getpid () != 0 | |
324 | ? MP_NAPROCS | |
325 | : MP_NPROCS); | |
326 | if (nprocs > 0) | |
327 | return nprocs; | |
328 | } | |
329 | #endif | |
330 | ||
331 | /* Finally, as fallback, use the APIs that don't distinguish between | |
332 | NPROC_CURRENT and NPROC_ALL. */ | |
333 | ||
334 | #if HAVE_SYSCTL && defined HW_NCPU | |
005de2e8 | 335 | { /* This works on Mac OS X, FreeBSD, NetBSD, OpenBSD. */ |
0f00f2c3 LC |
336 | int nprocs; |
337 | size_t len = sizeof (nprocs); | |
338 | static int mib[2] = { CTL_HW, HW_NCPU }; | |
339 | ||
340 | if (sysctl (mib, ARRAY_SIZE (mib), &nprocs, &len, NULL, 0) == 0 | |
341 | && len == sizeof (nprocs) | |
342 | && 0 < nprocs) | |
343 | return nprocs; | |
344 | } | |
345 | #endif | |
346 | ||
347 | #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__ | |
348 | { /* This works on native Windows platforms. */ | |
349 | SYSTEM_INFO system_info; | |
350 | GetSystemInfo (&system_info); | |
351 | if (0 < system_info.dwNumberOfProcessors) | |
352 | return system_info.dwNumberOfProcessors; | |
353 | } | |
354 | #endif | |
355 | ||
356 | return 1; | |
357 | } |