Current File : //usr/share/cmake/Modules/ProcessorCount.cmake
# - ProcessorCount(var)
# Determine the number of processors/cores and save value in ${var}
#
# Sets the variable named ${var} to the number of physical cores available on
# the machine if the information can be determined. Otherwise it is set to 0.
# Currently this functionality is implemented for AIX, cygwin, FreeBSD, HPUX,
# IRIX, Linux, Mac OS X, QNX, Sun and Windows.
#
# This function is guaranteed to return a positive integer (>=1) if it
# succeeds. It returns 0 if there's a problem determining the processor count.
#
# Example use, in a ctest -S dashboard script:
#
# include(ProcessorCount)
# ProcessorCount(N)
# if(NOT N EQUAL 0)
# set(CTEST_BUILD_FLAGS -j${N})
# set(ctest_test_args ${ctest_test_args} PARALLEL_LEVEL ${N})
# endif()
#
# This function is intended to offer an approximation of the value of the
# number of compute cores available on the current machine, such that you
# may use that value for parallel building and parallel testing. It is meant
# to help utilize as much of the machine as seems reasonable. Of course,
# knowledge of what else might be running on the machine simultaneously
# should be used when deciding whether to request a machine's full capacity
# all for yourself.
# A more reliable way might be to compile a small C program that uses the CPUID
# instruction, but that again requires compiler support or compiling assembler
# code.
#=============================================================================
# Copyright 2010-2011 Kitware, Inc.
#
# Distributed under the OSI-approved BSD License (the "License");
# see accompanying file Copyright.txt for details.
#
# This software is distributed WITHOUT ANY WARRANTY; without even the
# implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
# See the License for more information.
#=============================================================================
# (To distribute this file outside of CMake, substitute the full
# License text for the above reference.)
function(ProcessorCount var)
# Unknown:
set(count 0)
if(WIN32)
# Windows:
set(count "$ENV{NUMBER_OF_PROCESSORS}")
#message("ProcessorCount: WIN32, trying environment variable")
endif()
if(NOT count)
# Mac, FreeBSD, OpenBSD (systems with sysctl):
find_program(ProcessorCount_cmd_sysctl sysctl
PATHS /usr/sbin /sbin)
mark_as_advanced(ProcessorCount_cmd_sysctl)
if(ProcessorCount_cmd_sysctl)
execute_process(COMMAND ${ProcessorCount_cmd_sysctl} -n hw.ncpu
ERROR_QUIET
OUTPUT_STRIP_TRAILING_WHITESPACE
OUTPUT_VARIABLE count)
#message("ProcessorCount: trying sysctl '${ProcessorCount_cmd_sysctl}'")
endif()
endif()
if(NOT count)
# Linux (systems with getconf):
find_program(ProcessorCount_cmd_getconf getconf)
mark_as_advanced(ProcessorCount_cmd_getconf)
if(ProcessorCount_cmd_getconf)
execute_process(COMMAND ${ProcessorCount_cmd_getconf} _NPROCESSORS_ONLN
ERROR_QUIET
OUTPUT_STRIP_TRAILING_WHITESPACE
OUTPUT_VARIABLE count)
#message("ProcessorCount: trying getconf '${ProcessorCount_cmd_getconf}'")
endif()
endif()
if(NOT count)
# HPUX (systems with machinfo):
find_program(ProcessorCount_cmd_machinfo machinfo
PATHS /usr/contrib/bin)
mark_as_advanced(ProcessorCount_cmd_machinfo)
if(ProcessorCount_cmd_machinfo)
execute_process(COMMAND ${ProcessorCount_cmd_machinfo}
ERROR_QUIET
OUTPUT_STRIP_TRAILING_WHITESPACE
OUTPUT_VARIABLE machinfo_output)
string(REGEX MATCHALL "Number of CPUs = ([0-9]+)" procs "${machinfo_output}")
set(count "${CMAKE_MATCH_1}")
#message("ProcessorCount: trying machinfo '${ProcessorCount_cmd_machinfo}'")
endif()
endif()
if(NOT count)
# IRIX (systems with hinv):
find_program(ProcessorCount_cmd_hinv hinv
PATHS /sbin)
mark_as_advanced(ProcessorCount_cmd_hinv)
if(ProcessorCount_cmd_hinv)
execute_process(COMMAND ${ProcessorCount_cmd_hinv}
ERROR_QUIET
OUTPUT_STRIP_TRAILING_WHITESPACE
OUTPUT_VARIABLE hinv_output)
string(REGEX MATCHALL "([0-9]+) .* Processors" procs "${hinv_output}")
set(count "${CMAKE_MATCH_1}")
#message("ProcessorCount: trying hinv '${ProcessorCount_cmd_hinv}'")
endif()
endif()
if(NOT count)
# AIX (systems with lsconf):
find_program(ProcessorCount_cmd_lsconf lsconf
PATHS /usr/sbin)
mark_as_advanced(ProcessorCount_cmd_lsconf)
if(ProcessorCount_cmd_lsconf)
execute_process(COMMAND ${ProcessorCount_cmd_lsconf}
ERROR_QUIET
OUTPUT_STRIP_TRAILING_WHITESPACE
OUTPUT_VARIABLE lsconf_output)
string(REGEX MATCHALL "Number Of Processors: ([0-9]+)" procs "${lsconf_output}")
set(count "${CMAKE_MATCH_1}")
#message("ProcessorCount: trying lsconf '${ProcessorCount_cmd_lsconf}'")
endif()
endif()
if(NOT count)
# QNX (systems with pidin):
find_program(ProcessorCount_cmd_pidin pidin)
mark_as_advanced(ProcessorCount_cmd_pidin)
if(ProcessorCount_cmd_pidin)
execute_process(COMMAND ${ProcessorCount_cmd_pidin} info
ERROR_QUIET
OUTPUT_STRIP_TRAILING_WHITESPACE
OUTPUT_VARIABLE pidin_output)
string(REGEX MATCHALL "Processor[0-9]+: " procs "${pidin_output}")
list(LENGTH procs count)
#message("ProcessorCount: trying pidin '${ProcessorCount_cmd_pidin}'")
endif()
endif()
if(NOT count)
# Sun (systems where uname -X emits "NumCPU" in its output):
find_program(ProcessorCount_cmd_uname uname)
mark_as_advanced(ProcessorCount_cmd_uname)
if(ProcessorCount_cmd_uname)
execute_process(COMMAND ${ProcessorCount_cmd_uname} -X
ERROR_QUIET
OUTPUT_STRIP_TRAILING_WHITESPACE
OUTPUT_VARIABLE uname_X_output)
string(REGEX MATCHALL "NumCPU = ([0-9]+)" procs "${uname_X_output}")
set(count "${CMAKE_MATCH_1}")
#message("ProcessorCount: trying uname -X '${ProcessorCount_cmd_uname}'")
endif()
endif()
# Execute this code when all previously attempted methods return empty
# output:
#
if(NOT count)
# Systems with /proc/cpuinfo:
set(cpuinfo_file /proc/cpuinfo)
if(EXISTS "${cpuinfo_file}")
file(STRINGS "${cpuinfo_file}" procs REGEX "^processor.: [0-9]+$")
list(LENGTH procs count)
#message("ProcessorCount: trying cpuinfo '${cpuinfo_file}'")
endif()
endif()
# Since cygwin builds of CMake do not define WIN32 anymore, but they still
# run on Windows, and will still have this env var defined:
#
if(NOT count)
set(count "$ENV{NUMBER_OF_PROCESSORS}")
#message("ProcessorCount: last fallback, trying environment variable")
endif()
# Ensure an integer return (avoid inadvertently returning an empty string
# or an error string)... If it's not a decimal integer, return 0:
#
if(NOT count MATCHES "^[0-9]+$")
set(count 0)
endif()
set(${var} ${count} PARENT_SCOPE)
endfunction()
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