class Rake::CpuCounter

Based on a script at:

http://stackoverflow.com/questions/891537/ruby-detect-number-of-cpus-installed

Public Class Methods

count() click to toggle source
# File lib/rake/cpu_counter.rb, line 8
def self.count
  new.count_with_default
end

Public Instance Methods

count() click to toggle source
# File lib/rake/cpu_counter.rb, line 18
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
    else
      # Try everything
      count_via_win32 ||
        count_via_sysctl ||
        count_via_hwprefs_thread_count ||
        count_via_hwprefs_cpu_count
    end
  end
end
count_via_cpuinfo() click to toggle source
# File lib/rake/cpu_counter.rb, line 58
def count_via_cpuinfo
  open('/proc/cpuinfo') { |f| f.readlines }.grep(/processor/).size
rescue StandardError
  nil
end
count_via_hwprefs_cpu_count() click to toggle source
# File lib/rake/cpu_counter.rb, line 68
def count_via_hwprefs_cpu_count
  run 'hwprefs', 'cpu_count'
end
count_via_hwprefs_thread_count() click to toggle source
# File lib/rake/cpu_counter.rb, line 64
def count_via_hwprefs_thread_count
  run 'hwprefs', 'thread_count'
end
count_via_java_runtime() click to toggle source
# File lib/rake/cpu_counter.rb, line 43
def count_via_java_runtime
  Java::Java.lang.Runtime.getRuntime.availableProcessors
rescue StandardError
  nil
end
count_via_sysctl() click to toggle source
# File lib/rake/cpu_counter.rb, line 72
def count_via_sysctl
  run 'sysctl', '-n hw.ncpu'
end
count_via_win32() click to toggle source
# File lib/rake/cpu_counter.rb, line 49
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
rescue StandardError
  nil
end
count_with_default(default=4) click to toggle source
# File lib/rake/cpu_counter.rb, line 12
def count_with_default(default=4)
  count || default
rescue StandardError
  default
end
in_path_command(command) click to toggle source
# File lib/rake/cpu_counter.rb, line 96
def in_path_command(command)
  %xwhich #{command}` != '' ? command : nil
end
look_for_command(dir, command) click to toggle source
# File lib/rake/cpu_counter.rb, line 91
def look_for_command(dir, command)
  path = File.join(dir, command)
  File.exist?(path) ? path : nil
end
resolve_command(command) click to toggle source
# File lib/rake/cpu_counter.rb, line 85
def resolve_command(command)
  look_for_command("/usr/sbin", command) ||
    look_for_command("/sbin", command) ||
    in_path_command(command)
end
run(command, args) click to toggle source
# File lib/rake/cpu_counter.rb, line 76
def run(command, args)
  cmd = resolve_command(command)
  if cmd
    %x#{cmd} #{args}`.to_i
  else
    nil
  end
end