Class: NewRelic::Agent::Samplers::CpuSampler

Inherits:
NewRelic::Agent::Sampler show all
Defined in:
lib/new_relic/agent/samplers/cpu_sampler.rb

Instance Attribute Summary collapse

Attributes inherited from NewRelic::Agent::Sampler

#id

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from NewRelic::Agent::Sampler

enabled?, inherited, named, sampler_classes

Constructor Details

#initialize ⇒ CpuSampler

Returns a new instance of CpuSampler.



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# 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

Instance Attribute Details

#last_time ⇒ Object (readonly)

Returns the value of attribute last_time.



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# File 'lib/new_relic/agent/samplers/cpu_sampler.rb', line 11

def last_time
  @last_time
end

Class Method Details

.supported_on_this_platform? ⇒ Boolean

Returns:

  • (Boolean) 


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# 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

Instance Method Details

#poll ⇒ Object 



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# 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) ⇒ Object 



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# 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) ⇒ Object 



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# 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) ⇒ Object 



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# 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) ⇒ Object 



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# File 'lib/new_relic/agent/samplers/cpu_sampler.rb', line 33

def record_usertime(value)
  NewRelic::Agent.record_metric('CPU/User Time', value)
end