Modules/ProcessorCount.cmake - third_party/cmake - Git at Google

 # - 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)
     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)
     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)
     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)
     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)
     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)
     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)
     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()
	# - 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)
	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)
	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)
	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)
	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)
	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)
	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)
	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()