Class: Hyperctl::Sysfs

Inherits:
Object
  • Object
show all
Defined in:
lib/hyperctl/sysfs.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Sysfs

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns a new instance of Sysfs.



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# File 'lib/hyperctl/sysfs.rb', line 8

def initialize
  @cpu_info = refresh
end

Instance Attribute Details

#cpu_info ⇒ Object

Returns the value of attribute cpu_info.



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# File 'lib/hyperctl/sysfs.rb', line 5

def cpu_info
  @cpu_info
end

Class Method Details

.disable_core(core_id) ⇒ Object

Disable a CPU by numeric core id

Parameters:

  • core_id (Integer) 


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# File 'lib/hyperctl/sysfs.rb', line 174

def self.disable_core(core_id)
  set_core(core_id, '0')
end

.enable_core(core_id) ⇒ Object

Enable a CPU by numeric core id

Parameters:

  • core_id (Integer) 


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# File 'lib/hyperctl/sysfs.rb', line 166

def self.enable_core(core_id)
  set_core(core_id, '1')
end

Instance Method Details

#all_cores_enabled? ⇒ Bool

Are all phyical/hyperthread/SMT/sibling cores enabled?

Returns:

  • (Bool) —

    of status



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# File 'lib/hyperctl/sysfs.rb', line 150

def all_cores_enabled?
  cores.count == online_cores.count
end

#all_siblings_disabled? ⇒ Bool

Are all hyperthread/SMT/sibling cores Disabled?

Returns:

  • (Bool) —

    of status



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# File 'lib/hyperctl/sysfs.rb', line 158

def all_siblings_disabled?
  sibling_cores.empty?
end

#cores ⇒ Array<Integer>

List of all CPUs in system by numeric core id

Returns:

  • (Array<Integer>) —

    of core ids



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# File 'lib/hyperctl/sysfs.rb', line 79

def cores
  cores = []
  cpu_info.each_key.sort_by {|k| cpu_info[k][:core_id] }.each do |k|
    cores << cpu_info[k][:core_id]
  end

  return cores
end

#offline_cores ⇒ Array<Integer>

List of offline CPUs in system by numeric core id

Returns:

  • (Array<Integer>) —

    of core ids



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# File 'lib/hyperctl/sysfs.rb', line 108

def offline_cores
  cores = []
  cpu_info.each_key.sort_by {|k| cpu_info[k][:core_id] }.each do |k|
    core_id = cpu_info[k][:core_id]
    if cpu_info[k][:online] == false
      cores << core_id
    end
  end

  return cores
end

#online_cores ⇒ Array<Integer>

List of online CPUs in system by numeric core id

Returns:

  • (Array<Integer>) —

    of core ids



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# File 'lib/hyperctl/sysfs.rb', line 92

def online_cores
  cores = []
  cpu_info.each_key.sort_by {|k| cpu_info[k][:core_id] }.each do |k|
    core_id = cpu_info[k][:core_id]
    if cpu_info[k][:online] == true
      cores << core_id
    end
  end

  return cores
end

#refresh ⇒ Hash

Refresh the cpu_info [Hash] of the current CPU states

Returns:

  • (Hash) —

    of cpu status



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# File 'lib/hyperctl/sysfs.rb', line 16

def refresh
  info = {}

  # get a listing of all cpu cores
  cpu_dirs = Dir.glob('/sys/devices/system/cpu/cpu[0-9]*')

  cpu_dirs.each do |d|
    # find the "name" of the cpu based on the sysfs dir. Eg, cpu15
    cpu_name = File.basename d
    cpu_idx = cpu_name.to_sym
    info[cpu_idx] = { :name => cpu_name }

    # find the numeric core_id. Eg, 15 in sysfs as
    # /sys/devices/system/cpu/cpu3/topology/core_id but we can parse it from
    # the path
    core_id = cpu_name.match(/cpu(\d+)/)[1].to_i
    info[cpu_idx][:core_id] = core_id

    # is the cpu online?
    # if a CPU is online, /sys/devices/system/cpu/cpu1/online will be 1,
    # otherwise 0.  cpu0 appears to be special and does not have the online
    # sysfs entry on any of the systems I inspected. I suspect that it might
    # get this attribute if CONFIG_BOOTPARAM_HOTPLUG_CPU0 is enabled per
    # https://www.kernel.org/doc/Documentation/cpu-hotplug.txt
    path = File.join(d, 'online')
    online = false
    if File.exist?(path)
      online = to_bool(File.read(path).chomp)
    elsif core_id == 0
      # cpu0 gets a special pass if the online attr is missing
      online = true
    end
    info[cpu_idx][:online] = online

    next unless online

    # does the cpu have any [SMT] siblings?
    # The attr /sys/devices/system/cpu/cpu6/topology/thread_siblings_list
    # will list all siblings including the cpu's own core_id This attr is not
    # present if the cpu is offline This attr is not present under EL5.x
    # (2.6.18-164.el5PAE) on the one system I inspected that appears to have
    # HT disabled in the bios (/proc/cpuinfo shows the ht cpu flag but
    # there's no siblings list)
    path = File.join(d, 'topology/thread_siblings_list')
    if File.exist?(path)
      sibs = File.read(path).chomp.split(',')
      # convert core_id(s) to be numeric
      sibs.map! {|s| s.to_i }
      # remove the cpu's core_id from the list
      sibs = sibs - [ core_id ]
      unless sibs.empty?
        info[cpu_idx][:thread_siblings_list] = sibs
      end
    end
  end

  @cpu_info = info
end

#sibling_cores ⇒ Array<Integer>

List of sibling (aka hyperthread/SMT) CPUs in system by numeric core id

Returns:

  • (Array<Integer>) —

    of core ids



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# File 'lib/hyperctl/sysfs.rb', line 124

def sibling_cores
  cores = []
  checked_cores = []
  cpu_info.each_key.sort_by {|k| cpu_info[k][:core_id] }.each do |k|
    cpu = cpu_info[k]
    checked_cores << cpu[:core_id]

    if cpu.has_key?(:thread_siblings_list)
      (cpu[:thread_siblings_list] - checked_cores).each do |core_id|
        # check to see if the core is already disabled
        # XXX this probably isn't nessicary as a disabled core appears to #
        # never be listed as a sibiling
        if cpu_info[k][:online] == true
          cores << core_id
        end
      end
    end
  end

  return cores
end