# SPDX-License-Identifier: 0BSD ############################################################################# # # tuklib_cpucores.cmake - see tuklib_cpucores.m4 for description and comments # # Author: Lasse Collin # ############################################################################# include("${CMAKE_CURRENT_LIST_DIR}/tuklib_common.cmake") include(CheckCSourceCompiles) include(CheckIncludeFile) function(tuklib_cpucores_internal_check) if(WIN32 OR CYGWIN) # Nothing to do, the tuklib_cpucores.c handles it. set(TUKLIB_CPUCORES_DEFINITIONS "" CACHE INTERNAL "") return() endif() # glibc-based systems (GNU/Linux and GNU/kFreeBSD) have # sched_getaffinity(). The CPU_COUNT() macro was added in glibc 2.9. # glibc 2.9 is old enough that if someone uses the code on older glibc, # the fallback to sysconf() should be good enough. # # NOTE: This required that _GNU_SOURCE is defined. We assume that whatever # feature test macros the caller wants to use are already set in # CMAKE_REQUIRED_DEFINES and in the target defines. check_c_source_compiles(" #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_CPUCORES_SCHED_GETAFFINITY) if(TUKLIB_CPUCORES_SCHED_GETAFFINITY) set(TUKLIB_CPUCORES_DEFINITIONS "TUKLIB_CPUCORES_SCHED_GETAFFINITY" CACHE INTERNAL "") return() endif() # 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. check_c_source_compiles(" #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_CPUCORES_CPUSET) if(TUKLIB_CPUCORES_CPUSET) set(TUKLIB_CPUCORES_DEFINITIONS "HAVE_PARAM_H;TUKLIB_CPUCORES_CPUSET" CACHE INTERNAL "") return() endif() # 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. check_include_file(sys/param.h HAVE_SYS_PARAM_H) if(HAVE_SYS_PARAM_H) list(APPEND CMAKE_REQUIRED_DEFINITIONS -DHAVE_SYS_PARAM_H) endif() check_c_source_compiles(" #ifdef __QNX__ compile error #endif #ifdef HAVE_SYS_PARAM_H # include <sys/param.h> #endif #include <sys/sysctl.h> int main(void) { #ifdef HW_NCPUONLINE /* This is preferred on OpenBSD, see tuklib_cpucores.c. */ int name[2] = { CTL_HW, HW_NCPUONLINE }; #else int name[2] = { CTL_HW, HW_NCPU }; #endif int cpus; size_t cpus_size = sizeof(cpus); sysctl(name, 2, &cpus, &cpus_size, NULL, 0); return 0; } " TUKLIB_CPUCORES_SYSCTL) if(TUKLIB_CPUCORES_SYSCTL) if(HAVE_SYS_PARAM_H) set(TUKLIB_CPUCORES_DEFINITIONS "HAVE_PARAM_H;TUKLIB_CPUCORES_SYSCTL" CACHE INTERNAL "") else() set(TUKLIB_CPUCORES_DEFINITIONS "TUKLIB_CPUCORES_SYSCTL" CACHE INTERNAL "") endif() return() endif() # Many platforms support sysconf(). check_c_source_compiles(" #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_CPUCORES_SYSCONF) if(TUKLIB_CPUCORES_SYSCONF) set(TUKLIB_CPUCORES_DEFINITIONS "TUKLIB_CPUCORES_SYSCONF" CACHE INTERNAL "") return() endif() # HP-UX check_c_source_compiles(" #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_CPUCORES_PSTAT_GETDYNAMIC) if(TUKLIB_CPUCORES_PSTAT_GETDYNAMIC) set(TUKLIB_CPUCORES_DEFINITIONS "TUKLIB_CPUCORES_PSTAT_GETDYNAMIC" CACHE INTERNAL "") return() endif() endfunction() function(tuklib_cpucores TARGET_OR_ALL) if(NOT DEFINED TUKLIB_CPUCORES_FOUND) message(STATUS "Checking how to detect the number of available CPU cores") tuklib_cpucores_internal_check() if(DEFINED TUKLIB_CPUCORES_DEFINITIONS) set(TUKLIB_CPUCORES_FOUND 1 CACHE INTERNAL "") else() set(TUKLIB_CPUCORES_FOUND 0 CACHE INTERNAL "") message(WARNING "No method to detect the number of CPU cores was found") endif() endif() if(TUKLIB_CPUCORES_FOUND) tuklib_add_definitions("${TARGET_OR_ALL}" "${TUKLIB_CPUCORES_DEFINITIONS}") endif() endfunction()