# # SYNOPSIS # # TUKLIB_CPUCORES # # DESCRIPTION # # Check how to find out the number of available CPU cores in the system. # This information is used by tuklib_cpucores.c. # # Supported methods: # - GetSystemInfo(): Windows (including Cygwin) # - sched_getaffinity(): glibc (GNU/Linux, GNU/kFreeBSD) # - cpuset_getaffinity(): FreeBSD # - sysctl(): BSDs, OS/2 # - sysconf(): GNU/Linux, Solaris, Tru64, IRIX, AIX, QNX, Cygwin (but # GetSystemInfo() is used on Cygwin) # - pstat_getdynamic(): HP-UX # # COPYING # # Author: Lasse Collin # # This file has been put into the public domain. # You can do whatever you want with this file. # AC_DEFUN_ONCE([TUKLIB_CPUCORES], [ AC_REQUIRE([TUKLIB_COMMON]) # sys/param.h might be needed by sys/sysctl.h. AC_CHECK_HEADERS([sys/param.h]) AC_CACHE_CHECK([how to detect the number of available CPU cores], [tuklib_cv_cpucores_method], [ # Maybe checking $host_os would be enough but this matches what # tuklib_cpucores.c does. # # NOTE: IRIX has a compiler that doesn't error out with #error, so use # a non-compilable text instead of #error to generate an error. AC_COMPILE_IFELSE([AC_LANG_SOURCE([[ #if defined(_WIN32) || defined(__CYGWIN__) int main(void) { return 0; } #else compile error #endif ]])], [tuklib_cv_cpucores_method=special], [ # glibc-based systems (GNU/Linux and GNU/kFreeBSD) have sched_getaffinity(). # The CPU_COUNT() macro was added in glibc 2.9 so we try to link the # test program instead of merely compiling it. glibc 2.9 is old enough that # if someone uses the code on older glibc, the fallback to sysconf() should # be good enough. AC_LINK_IFELSE([AC_LANG_SOURCE([[ #include <sched.h> int main(void) { cpu_set_t cpu_mask; sched_getaffinity(0, sizeof(cpu_mask), &cpu_mask); return CPU_COUNT(&cpu_mask); } ]])], [tuklib_cv_cpucores_method=sched_getaffinity], [ # FreeBSD has both cpuset and sysctl. Look for cpuset first because # it's a better approach. # # This test would match on GNU/kFreeBSD too but it would require # -lfreebsd-glue when linking and thus in the current form this would # fail on GNU/kFreeBSD. The above test for sched_getaffinity() matches # on GNU/kFreeBSD so the test below should never run on that OS. AC_COMPILE_IFELSE([AC_LANG_SOURCE([[ #include <sys/param.h> #include <sys/cpuset.h> int main(void) { cpuset_t set; cpuset_getaffinity(CPU_LEVEL_WHICH, CPU_WHICH_PID, -1, sizeof(set), &set); return 0; } ]])], [tuklib_cv_cpucores_method=cpuset], [ # On OS/2, both sysconf() and sysctl() pass the tests in this file, # but only sysctl() works. On QNX it's the opposite: only sysconf() works # (although it assumes that _POSIX_SOURCE, _XOPEN_SOURCE, and _POSIX_C_SOURCE # are undefined or alternatively _QNX_SOURCE is defined). # # We test sysctl() first and intentionally break the sysctl() test on QNX # so that sysctl() is never used on QNX. AC_COMPILE_IFELSE([AC_LANG_SOURCE([[ #ifdef __QNX__ compile error #endif #include <sys/types.h> #ifdef HAVE_SYS_PARAM_H # include <sys/param.h> #endif #include <sys/sysctl.h> int main(void) { int name[2] = { CTL_HW, HW_NCPU }; int cpus; size_t cpus_size = sizeof(cpus); sysctl(name, 2, &cpus, &cpus_size, NULL, 0); return 0; } ]])], [tuklib_cv_cpucores_method=sysctl], [ AC_COMPILE_IFELSE([AC_LANG_SOURCE([[ #include <unistd.h> int main(void) { long i; #ifdef _SC_NPROCESSORS_ONLN /* Many systems using sysconf() */ i = sysconf(_SC_NPROCESSORS_ONLN); #else /* IRIX */ i = sysconf(_SC_NPROC_ONLN); #endif return 0; } ]])], [tuklib_cv_cpucores_method=sysconf], [ AC_COMPILE_IFELSE([AC_LANG_SOURCE([[ #include <sys/param.h> #include <sys/pstat.h> int main(void) { struct pst_dynamic pst; pstat_getdynamic(&pst, sizeof(pst), 1, 0); (void)pst.psd_proc_cnt; return 0; } ]])], [tuklib_cv_cpucores_method=pstat_getdynamic], [ tuklib_cv_cpucores_method=unknown ])])])])])])]) case $tuklib_cv_cpucores_method in sched_getaffinity) AC_DEFINE([TUKLIB_CPUCORES_SCHED_GETAFFINITY], [1], [Define to 1 if the number of available CPU cores can be detected with sched_getaffinity()]) ;; cpuset) AC_DEFINE([TUKLIB_CPUCORES_CPUSET], [1], [Define to 1 if the number of available CPU cores can be detected with cpuset(2).]) ;; sysctl) AC_DEFINE([TUKLIB_CPUCORES_SYSCTL], [1], [Define to 1 if the number of available CPU cores can be detected with sysctl().]) ;; sysconf) AC_DEFINE([TUKLIB_CPUCORES_SYSCONF], [1], [Define to 1 if the number of available CPU cores can be detected with sysconf(_SC_NPROCESSORS_ONLN) or sysconf(_SC_NPROC_ONLN).]) ;; pstat_getdynamic) AC_DEFINE([TUKLIB_CPUCORES_PSTAT_GETDYNAMIC], [1], [Define to 1 if the number of available CPU cores can be detected with pstat_getdynamic().]) ;; esac ])dnl