class NewRelic::Agent::Samplers::CpuSampler

Attributes

last_time[R]

Public Class Methods

new() click to toggle source
# File lib/new_relic/agent/samplers/cpu_sampler.rb, line 15
def initialize
  @last_time = nil
  @processor_count = NewRelic::Agent::SystemInfo.num_logical_processors
  if @processor_count.nil?
    NewRelic::Agent.logger.warn('Failed to determine processor count, assuming 1')
    @processor_count = 1
  end
  poll
end
supported_on_this_platform?() click to toggle source
# File lib/new_relic/agent/samplers/cpu_sampler.rb, line 41
def self.supported_on_this_platform?
  # Process.times on JRuby < 1.7.0 reports wall clock elapsed time,
  # not actual cpu time used, so this sampler can only be used on JRuby >= 1.7.0.
  if defined?(JRuby)
    return JRUBY_VERSION >= '1.7.0'
  end

  true
end

Public Instance Methods

poll() click to toggle source
# File lib/new_relic/agent/samplers/cpu_sampler.rb, line 51
def poll
  now = Process.clock_gettime(Process::CLOCK_MONOTONIC)
  t = Process.times

  if @last_time && t.utime != 0.0 && t.stime != 0.0
    elapsed = now - @last_time
    return if elapsed < 1 # Causing some kind of math underflow

    usertime = t.utime - @last_utime
    systemtime = t.stime - @last_stime

    record_systemtime(systemtime) if systemtime >= 0
    record_usertime(usertime) if usertime >= 0

    # Calculate the true utilization by taking cpu times and dividing by
    # elapsed time X processor_count.
    record_user_util(usertime / (elapsed * @processor_count))
    record_system_util(systemtime / (elapsed * @processor_count))
  end

  @last_utime = t.utime
  @last_stime = t.stime
  @last_time = now
end
record_system_util(value) click to toggle source
# File lib/new_relic/agent/samplers/cpu_sampler.rb, line 29
def record_system_util(value)
  NewRelic::Agent.record_metric('CPU/System/Utilization', value)
end
record_systemtime(value) click to toggle source
# File lib/new_relic/agent/samplers/cpu_sampler.rb, line 37
def record_systemtime(value)
  NewRelic::Agent.record_metric('CPU/System Time', value)
end
record_user_util(value) click to toggle source
# File lib/new_relic/agent/samplers/cpu_sampler.rb, line 25
def record_user_util(value)
  NewRelic::Agent.record_metric('CPU/User/Utilization', value)
end
record_usertime(value) click to toggle source
# File lib/new_relic/agent/samplers/cpu_sampler.rb, line 33
def record_usertime(value)
  NewRelic::Agent.record_metric('CPU/User Time', value)
end