Class: Amalgalite::ProfileSampler

Inherits:
Object
  • Object
show all
Defined in:
lib/amalgalite/profile_tap.rb

Overview

A ProfileSampler is a sampler of profile times. It aggregates up profile events that happen for the same source. It is based upon the RFuzz::Sampler class from the rfuzz gem

Instance Method Summary collapse

Constructor Details

#initialize(name) ⇒ ProfileSampler

create a new sampler with the given name



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# File 'lib/amalgalite/profile_tap.rb', line 16

def initialize( name )
  @name = name
  reset!
end

Instance Method Details

#mean ⇒ Object

return the mean of the data



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# File 'lib/amalgalite/profile_tap.rb', line 50

def mean
  @sum / @n
end

#reset! ⇒ Object

reset the internal state so it may be used again



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# File 'lib/amalgalite/profile_tap.rb', line 24

def reset!
  @sum   = 0.0
  @sumsq = 0.0
  @n     = 0
  @min   = 0.0
  @max   = 0.0
end

#sample(value) ⇒ Object

add a sample to the calculations



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# File 'lib/amalgalite/profile_tap.rb', line 35

def sample( value )
  @sum   += value
  @sumsq += (value * value)
  if @n == 0 then
    @min = @max = value
  else
    @min = value if value < @min
    @max = value if value > @max
  end
  @n += 1
end

#stddev ⇒ Object

returns the standard deviation of the data



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# File 'lib/amalgalite/profile_tap.rb', line 57

def stddev
  begin
    return 0.0 if ( 1 == @n )
    Math.sqrt( (@sumsq - ( @sum * @sum / @n)) / (@n-1) )
  rescue Errno::EDOM
    return 0.0
  end
end

#to_a ⇒ Object

return all the values as an array



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# File 'lib/amalgalite/profile_tap.rb', line 69

def to_a
  [ @name, @sum, @sumsq, @n, mean, stddev, @min, @max ]
end

#to_h ⇒ Object

return all the values as a hash



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# File 'lib/amalgalite/profile_tap.rb', line 76

def to_h
  { 'name'    => @name,  'n' => @n,
    'sum'     => @sum,   'sumsq'   => @sumsq, 'mean'    => mean,
    'stddev'  => stddev, 'min'     => @min,   'max'     => @max }
end

#to_s ⇒ Object

return a string containing the sampler summary



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# File 'lib/amalgalite/profile_tap.rb', line 85

def to_s
  "[%s] => sum: %d, sumsq: %d, n: %d, mean: %0.6f, stddev: %0.6f, min: %d, max: %d" % self.to_a
end