xz/cmake/tuklib_cpucores.cmake

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#
# tuklib_cpucores.cmake - see tuklib_cpucores.m4 for description and comments
#
# Author: Lasse Collin
#
# This file has been put into the public domain.
# You can do whatever you want with this file.
#
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()