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#--
# benchmark.rb - a performance benchmarking library
#
# $Id: benchmark.rb 43002 2013-09-20 16:05:48Z zzak $
#
# Created by Gotoken (gotoken@notwork.org).
#
# Documentation by Gotoken (original RD), Lyle Johnson (RDoc conversion), and
# Gavin Sinclair (editing).
#++
#
# == Overview
#
# The Benchmark module provides methods for benchmarking Ruby code, giving
# detailed reports on the time taken for each task.
#
# The Benchmark module provides methods to measure and report the time
# used to execute Ruby code.
#
# * Measure the time to construct the string given by the expression
# <code>"a"*1_000_000_000</code>:
#
# require 'benchmark'
#
# puts Benchmark.measure { "a"*1_000_000_000 }
#
# On my machine (OSX 10.8.3 on i5 1.7 Ghz) this generates:
#
# 0.350000 0.400000 0.750000 ( 0.835234)
#
# This report shows the user CPU time, system CPU time, the sum of
# the user and system CPU times, and the elapsed real time. The unit
# of time is seconds.
#
# * Do some experiments sequentially using the #bm method:
#
# require 'benchmark'
#
# n = 5000000
# Benchmark.bm do |x|
# x.report { for i in 1..n; a = "1"; end }
# x.report { n.times do ; a = "1"; end }
# x.report { 1.upto(n) do ; a = "1"; end }
# end
#
# The result:
#
# user system total real
# 1.010000 0.000000 1.010000 ( 1.014479)
# 1.000000 0.000000 1.000000 ( 0.998261)
# 0.980000 0.000000 0.980000 ( 0.981335)
#
# * Continuing the previous example, put a label in each report:
#
# require 'benchmark'
#
# n = 5000000
# Benchmark.bm(7) do |x|
# x.report("for:") { for i in 1..n; a = "1"; end }
# x.report("times:") { n.times do ; a = "1"; end }
# x.report("upto:") { 1.upto(n) do ; a = "1"; end }
# end
#
# The result:
#
# user system total real
# for: 1.010000 0.000000 1.010000 ( 1.015688)
# times: 1.000000 0.000000 1.000000 ( 1.003611)
# upto: 1.030000 0.000000 1.030000 ( 1.028098)
#
# * The times for some benchmarks depend on the order in which items
# are run. These differences are due to the cost of memory
# allocation and garbage collection. To avoid these discrepancies,
# the #bmbm method is provided. For example, to compare ways to
# sort an array of floats:
#
# require 'benchmark'
#
# array = (1..1000000).map { rand }
#
# Benchmark.bmbm do |x|
# x.report("sort!") { array.dup.sort! }
# x.report("sort") { array.dup.sort }
# end
#
# The result:
#
# Rehearsal -----------------------------------------
# sort! 1.490000 0.010000 1.500000 ( 1.490520)
# sort 1.460000 0.000000 1.460000 ( 1.463025)
# -------------------------------- total: 2.960000sec
#
# user system total real
# sort! 1.460000 0.000000 1.460000 ( 1.460465)
# sort 1.450000 0.010000 1.460000 ( 1.448327)
#
# * Report statistics of sequential experiments with unique labels,
# using the #benchmark method:
#
# require 'benchmark'
# include Benchmark # we need the CAPTION and FORMAT constants
#
# n = 5000000
# Benchmark.benchmark(CAPTION, 7, FORMAT, ">total:", ">avg:") do |x|
# tf = x.report("for:") { for i in 1..n; a = "1"; end }
# tt = x.report("times:") { n.times do ; a = "1"; end }
# tu = x.report("upto:") { 1.upto(n) do ; a = "1"; end }
# [tf+tt+tu, (tf+tt+tu)/3]
# end
#
# The result:
#
# user system total real
# for: 0.950000 0.000000 0.950000 ( 0.952039)
# times: 0.980000 0.000000 0.980000 ( 0.984938)
# upto: 0.950000 0.000000 0.950000 ( 0.946787)
# >total: 2.880000 0.000000 2.880000 ( 2.883764)
# >avg: 0.960000 0.000000 0.960000 ( 0.961255)
module Benchmark
BENCHMARK_VERSION = "2002-04-25" # :nodoc:
# Invokes the block with a Benchmark::Report object, which
# may be used to collect and report on the results of individual
# benchmark tests. Reserves +label_width+ leading spaces for
# labels on each line. Prints +caption+ at the top of the
# report, and uses +format+ to format each line.
# Returns an array of Benchmark::Tms objects.
#
# If the block returns an array of
# Benchmark::Tms objects, these will be used to format
# additional lines of output. If +label+ parameters are
# given, these are used to label these extra lines.
#
# _Note_: Other methods provide a simpler interface to this one, and are
# suitable for nearly all benchmarking requirements. See the examples in
# Benchmark, and the #bm and #bmbm methods.
#
# Example:
#
# require 'benchmark'
# include Benchmark # we need the CAPTION and FORMAT constants
#
# n = 5000000
# Benchmark.benchmark(CAPTION, 7, FORMAT, ">total:", ">avg:") do |x|
# tf = x.report("for:") { for i in 1..n; a = "1"; end }
# tt = x.report("times:") { n.times do ; a = "1"; end }
# tu = x.report("upto:") { 1.upto(n) do ; a = "1"; end }
# [tf+tt+tu, (tf+tt+tu)/3]
# end
#
# Generates:
#
# user system total real
# for: 0.970000 0.000000 0.970000 ( 0.970493)
# times: 0.990000 0.000000 0.990000 ( 0.989542)
# upto: 0.970000 0.000000 0.970000 ( 0.972854)
# >total: 2.930000 0.000000 2.930000 ( 2.932889)
# >avg: 0.976667 0.000000 0.976667 ( 0.977630)
#
def benchmark(caption = "", label_width = nil, format = nil, *labels) # :yield: report
sync = STDOUT.sync
STDOUT.sync = true
label_width ||= 0
label_width += 1
format ||= FORMAT
print ' '*label_width + caption unless caption.empty?
report = Report.new(label_width, format)
results = yield(report)
Array === results and results.grep(Tms).each {|t|
print((labels.shift || t.label || "").ljust(label_width), t.format(format))
}
report.list
ensure
STDOUT.sync = sync unless sync.nil?
end
# A simple interface to the #benchmark method, #bm generates sequential
# reports with labels. The parameters have the same meaning as for
# #benchmark.
#
# require 'benchmark'
#
# n = 5000000
# Benchmark.bm(7) do |x|
# x.report("for:") { for i in 1..n; a = "1"; end }
# x.report("times:") { n.times do ; a = "1"; end }
# x.report("upto:") { 1.upto(n) do ; a = "1"; end }
# end
#
# Generates:
#
# user system total real
# for: 0.960000 0.000000 0.960000 ( 0.957966)
# times: 0.960000 0.000000 0.960000 ( 0.960423)
# upto: 0.950000 0.000000 0.950000 ( 0.954864)
#
def bm(label_width = 0, *labels, &blk) # :yield: report
benchmark(CAPTION, label_width, FORMAT, *labels, &blk)
end
# Sometimes benchmark results are skewed because code executed
# earlier encounters different garbage collection overheads than
# that run later. #bmbm attempts to minimize this effect by running
# the tests twice, the first time as a rehearsal in order to get the
# runtime environment stable, the second time for
# real. GC.start is executed before the start of each of
# the real timings; the cost of this is not included in the
# timings. In reality, though, there's only so much that #bmbm can
# do, and the results are not guaranteed to be isolated from garbage
# collection and other effects.
#
# Because #bmbm takes two passes through the tests, it can
# calculate the required label width.
#
# require 'benchmark'
#
# array = (1..1000000).map { rand }
#
# Benchmark.bmbm do |x|
# x.report("sort!") { array.dup.sort! }
# x.report("sort") { array.dup.sort }
# end
#
# Generates:
#
# Rehearsal -----------------------------------------
# sort! 1.440000 0.010000 1.450000 ( 1.446833)
# sort 1.440000 0.000000 1.440000 ( 1.448257)
# -------------------------------- total: 2.890000sec
#
# user system total real
# sort! 1.460000 0.000000 1.460000 ( 1.458065)
# sort 1.450000 0.000000 1.450000 ( 1.455963)
#
# #bmbm yields a Benchmark::Job object and returns an array of
# Benchmark::Tms objects.
#
def bmbm(width = 0) # :yield: job
job = Job.new(width)
yield(job)
width = job.width + 1
sync = STDOUT.sync
STDOUT.sync = true
# rehearsal
puts 'Rehearsal '.ljust(width+CAPTION.length,'-')
ets = job.list.inject(Tms.new) { |sum,(label,item)|
print label.ljust(width)
res = Benchmark.measure(&item)
print res.format
sum + res
}.format("total: %tsec")
print " #{ets}\n\n".rjust(width+CAPTION.length+2,'-')
# take
print ' '*width + CAPTION
job.list.map { |label,item|
GC.start
print label.ljust(width)
Benchmark.measure(label, &item).tap { |res| print res }
}
ensure
STDOUT.sync = sync unless sync.nil?
end
#
# Returns the time used to execute the given block as a
# Benchmark::Tms object.
#
def measure(label = "") # :yield:
t0, r0 = Process.times, Time.now
yield
t1, r1 = Process.times, Time.now
Benchmark::Tms.new(t1.utime - t0.utime,
t1.stime - t0.stime,
t1.cutime - t0.cutime,
t1.cstime - t0.cstime,
r1 - r0,
label)
end
#
# Returns the elapsed real time used to execute the given block.
#
def realtime # :yield:
r0 = Time.now
yield
Time.now - r0
end
module_function :benchmark, :measure, :realtime, :bm, :bmbm
#
# A Job is a sequence of labelled blocks to be processed by the
# Benchmark.bmbm method. It is of little direct interest to the user.
#
class Job # :nodoc:
#
# Returns an initialized Job instance.
# Usually, one doesn't call this method directly, as new
# Job objects are created by the #bmbm method.
# +width+ is a initial value for the label offset used in formatting;
# the #bmbm method passes its +width+ argument to this constructor.
#
def initialize(width)
@width = width
@list = []
end
#
# Registers the given label and block pair in the job list.
#
def item(label = "", &blk) # :yield:
raise ArgumentError, "no block" unless block_given?
label = label.to_s
w = label.length
@width = w if @width < w
@list << [label, blk]
self
end
alias report item
# An array of 2-element arrays, consisting of label and block pairs.
attr_reader :list
# Length of the widest label in the #list.
attr_reader :width
end
#
# This class is used by the Benchmark.benchmark and Benchmark.bm methods.
# It is of little direct interest to the user.
#
class Report # :nodoc:
#
# Returns an initialized Report instance.
# Usually, one doesn't call this method directly, as new
# Report objects are created by the #benchmark and #bm methods.
# +width+ and +format+ are the label offset and
# format string used by Tms#format.
#
def initialize(width = 0, format = nil)
@width, @format, @list = width, format, []
end
#
# Prints the +label+ and measured time for the block,
# formatted by +format+. See Tms#format for the
# formatting rules.
#
def item(label = "", *format, &blk) # :yield:
print label.to_s.ljust(@width)
@list << res = Benchmark.measure(label, &blk)
print res.format(@format, *format)
res
end
alias report item
# An array of Benchmark::Tms objects representing each item.
attr_reader :list
end
#
# A data object, representing the times associated with a benchmark
# measurement.
#
class Tms
# Default caption, see also Benchmark::CAPTION
CAPTION = " user system total real\n"
# Default format string, see also Benchmark::FORMAT
FORMAT = "%10.6u %10.6y %10.6t %10.6r\n"
# User CPU time
attr_reader :utime
# System CPU time
attr_reader :stime
# User CPU time of children
attr_reader :cutime
# System CPU time of children
attr_reader :cstime
# Elapsed real time
attr_reader :real
# Total time, that is +utime+ + +stime+ + +cutime+ + +cstime+
attr_reader :total
# Label
attr_reader :label
#
# Returns an initialized Tms object which has
# +utime+ as the user CPU time, +stime+ as the system CPU time,
# +cutime+ as the children's user CPU time, +cstime+ as the children's
# system CPU time, +real+ as the elapsed real time and +label+ as the label.
#
def initialize(utime = 0.0, stime = 0.0, cutime = 0.0, cstime = 0.0, real = 0.0, label = nil)
@utime, @stime, @cutime, @cstime, @real, @label = utime, stime, cutime, cstime, real, label.to_s
@total = @utime + @stime + @cutime + @cstime
end
#
# Returns a new Tms object whose times are the sum of the times for this
# Tms object, plus the time required to execute the code block (+blk+).
#
def add(&blk) # :yield:
self + Benchmark.measure(&blk)
end
#
# An in-place version of #add.
#
def add!(&blk)
t = Benchmark.measure(&blk)
@utime = utime + t.utime
@stime = stime + t.stime
@cutime = cutime + t.cutime
@cstime = cstime + t.cstime
@real = real + t.real
self
end
#
# Returns a new Tms object obtained by memberwise summation
# of the individual times for this Tms object with those of the other
# Tms object.
# This method and #/() are useful for taking statistics.
#
def +(other); memberwise(:+, other) end
#
# Returns a new Tms object obtained by memberwise subtraction
# of the individual times for the other Tms object from those of this
# Tms object.
#
def -(other); memberwise(:-, other) end
#
# Returns a new Tms object obtained by memberwise multiplication
# of the individual times for this Tms object by _x_.
#
def *(x); memberwise(:*, x) end
#
# Returns a new Tms object obtained by memberwise division
# of the individual times for this Tms object by _x_.
# This method and #+() are useful for taking statistics.
#
def /(x); memberwise(:/, x) end
#
# Returns the contents of this Tms object as
# a formatted string, according to a format string
# like that passed to Kernel.format. In addition, #format
# accepts the following extensions:
#
# <tt>%u</tt>:: Replaced by the user CPU time, as reported by Tms#utime.
# <tt>%y</tt>:: Replaced by the system CPU time, as reported by #stime (Mnemonic: y of "s*y*stem")
# <tt>%U</tt>:: Replaced by the children's user CPU time, as reported by Tms#cutime
# <tt>%Y</tt>:: Replaced by the children's system CPU time, as reported by Tms#cstime
# <tt>%t</tt>:: Replaced by the total CPU time, as reported by Tms#total
# <tt>%r</tt>:: Replaced by the elapsed real time, as reported by Tms#real
# <tt>%n</tt>:: Replaced by the label string, as reported by Tms#label (Mnemonic: n of "*n*ame")
#
# If _format_ is not given, FORMAT is used as default value, detailing the
# user, system and real elapsed time.
#
def format(format = nil, *args)
str = (format || FORMAT).dup
str.gsub!(/(%[-+.\d]*)n/) { "#{$1}s" % label }
str.gsub!(/(%[-+.\d]*)u/) { "#{$1}f" % utime }
str.gsub!(/(%[-+.\d]*)y/) { "#{$1}f" % stime }
str.gsub!(/(%[-+.\d]*)U/) { "#{$1}f" % cutime }
str.gsub!(/(%[-+.\d]*)Y/) { "#{$1}f" % cstime }
str.gsub!(/(%[-+.\d]*)t/) { "#{$1}f" % total }
str.gsub!(/(%[-+.\d]*)r/) { "(#{$1}f)" % real }
format ? str % args : str
end
#
# Same as #format.
#
def to_s
format
end
#
# Returns a new 6-element array, consisting of the
# label, user CPU time, system CPU time, children's
# user CPU time, children's system CPU time and elapsed
# real time.
#
def to_a
[@label, @utime, @stime, @cutime, @cstime, @real]
end
protected
#
# Returns a new Tms object obtained by memberwise operation +op+
# of the individual times for this Tms object with those of the other
# Tms object.
#
# +op+ can be a mathematical operation such as <tt>+</tt>, <tt>-</tt>,
# <tt>*</tt>, <tt>/</tt>
#
def memberwise(op, x)
case x
when Benchmark::Tms
Benchmark::Tms.new(utime.__send__(op, x.utime),
stime.__send__(op, x.stime),
cutime.__send__(op, x.cutime),
cstime.__send__(op, x.cstime),
real.__send__(op, x.real)
)
else
Benchmark::Tms.new(utime.__send__(op, x),
stime.__send__(op, x),
cutime.__send__(op, x),
cstime.__send__(op, x),
real.__send__(op, x)
)
end
end
end
# The default caption string (heading above the output times).
CAPTION = Benchmark::Tms::CAPTION
# The default format string used to display times. See also Benchmark::Tms#format.
FORMAT = Benchmark::Tms::FORMAT
end
if __FILE__ == $0
include Benchmark
n = ARGV[0].to_i.nonzero? || 50000
puts %Q([#{n} times iterations of `a = "1"'])
benchmark(CAPTION, 7, FORMAT) do |x|
x.report("for:") {for _ in 1..n; _ = "1"; end} # Benchmark.measure
x.report("times:") {n.times do ; _ = "1"; end}
x.report("upto:") {1.upto(n) do ; _ = "1"; end}
end
benchmark do
[
measure{for _ in 1..n; _ = "1"; end}, # Benchmark.measure
measure{n.times do ; _ = "1"; end},
measure{1.upto(n) do ; _ = "1"; end}
]
end
end