jimweirich/cpu.rb

## cpu.rb
require 'rbconfig'

# Based on a script at:
#   http://stackoverflow.com/questions/891537/ruby-detect-number-of-cpus-installed
class CpuCounter
  def self.count
    new.count
  end

  def count
    if defined?(Java::Java)
      count_via_java_runtime
    else
      case RbConfig::CONFIG['host_os']
      when /darwin9/
        count_via_hwprefs_cpu_count
      when /darwin/
        count_via_hwprefs_thread_count || count_via_sysctl
      when /linux/
        count_via_cpuinfo
      when /freebsd/
        count_via_sysctl
      when /mswin|mingw/
        count_via_win32
      end
    end
  end

  def count_via_java_runtime
    Java::Java.lang.Runtime.getRuntime.availableProcessors
  end

  def count_via_win32
    require 'win32ole'
    wmi = WIN32OLE.connect("winmgmts://")
    cpu = wmi.ExecQuery("select NumberOfCores from Win32_Processor") # TODO count hyper-threaded in this
    cpu.to_enum.first.NumberOfCores
  end

  def count_via_cpuinfo
    open('/proc/cpuinfo') { |f| f.readlines }.grep(/processor/).size
  end

  def count_via_hwprefs_thread_count
    run 'hwprefs', 'thread_count'
  end

  def count_via_hwprefs_cpu_count
    run 'hwprefs', 'cpu_count'
  end

  def count_via_sysctl
    run 'sysctl', '-n hw.ncpu'
  end

  def run(command, args)
    cmd = resolve_command(command)
    if cmd
      `#{cmd} #{args}`.to_i
    else
      nil
    end
  end

  def resolve_command(command)
    try_command("/sbin", command) ||
      try_command("/usr/sbin", command) ||
      in_path_command(command)
  end

  def try_command(dir, command)
    path = File.join(dir, command)
    File.exist?(path) ? path : nil
  end

  def in_path_command(command)
    `which #{command}` != '' ? command : nil
  end
end

if $0 == __FILE__
  puts "Number of CPUs = #{CpuCounter.count}"
end
	require 'rbconfig'

	# Based on a script at:
	# http://stackoverflow.com/questions/891537/ruby-detect-number-of-cpus-installed
	class CpuCounter
	def self.count
	new.count
	end

	def count
	if defined?(Java::Java)
	count_via_java_runtime
	else
	case RbConfig::CONFIG['host_os']
	when /darwin9/
	count_via_hwprefs_cpu_count
	when /darwin/
	count_via_hwprefs_thread_count \|\| count_via_sysctl
	when /linux/
	count_via_cpuinfo
	when /freebsd/
	count_via_sysctl
	when /mswin\|mingw/
	count_via_win32
	end
	end
	end

	def count_via_java_runtime
	Java::Java.lang.Runtime.getRuntime.availableProcessors
	end

	def count_via_win32
	require 'win32ole'
	wmi = WIN32OLE.connect("winmgmts://")
	cpu = wmi.ExecQuery("select NumberOfCores from Win32_Processor") # TODO count hyper-threaded in this
	cpu.to_enum.first.NumberOfCores
	end

	def count_via_cpuinfo
	open('/proc/cpuinfo') { \|f\| f.readlines }.grep(/processor/).size
	end

	def count_via_hwprefs_thread_count
	run 'hwprefs', 'thread_count'
	end

	def count_via_hwprefs_cpu_count
	run 'hwprefs', 'cpu_count'
	end

	def count_via_sysctl
	run 'sysctl', '-n hw.ncpu'
	end

	def run(command, args)
	cmd = resolve_command(command)
	if cmd
	`#{cmd} #{args}`.to_i
	else
	nil
	end
	end

	def resolve_command(command)
	try_command("/sbin", command) \|\|
	try_command("/usr/sbin", command) \|\|
	in_path_command(command)
	end

	def try_command(dir, command)
	path = File.join(dir, command)
	File.exist?(path) ? path : nil
	end

	def in_path_command(command)
	`which #{command}` != '' ? command : nil
	end
	end

	if $0 == __FILE__
	puts "Number of CPUs = #{CpuCounter.count}"
	end