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April 17, 2012 01:12
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Benchmark from the Ruby Standard Library
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module Benchmark | |
BENCHMARK_VERSION = "2002-04-25" #:nodoc" | |
# Invokes the block with a <tt>Benchmark::Report</tt> object, which | |
# may be used to collect and report on the results of individual | |
# benchmark tests. Reserves <i>label_width</i> 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 | |
# <tt>Benchmark::Tms</tt> 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 = 50000 | |
# 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 | |
# | |
# <i>Generates:</i> | |
# | |
# user system total real | |
# for: 1.016667 0.016667 1.033333 ( 0.485749) | |
# times: 1.450000 0.016667 1.466667 ( 0.681367) | |
# upto: 1.533333 0.000000 1.533333 ( 0.722166) | |
# >total: 4.000000 0.033333 4.033333 ( 1.889282) | |
# >avg: 1.333333 0.011111 1.344444 ( 0.629761) | |
# | |
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 | |
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 is generates sequential reports | |
# with labels. The parameters have the same meaning as for #benchmark. | |
# | |
# require 'benchmark' | |
# | |
# n = 50000 | |
# 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 | |
# | |
# <i>Generates:</i> | |
# | |
# user system total real | |
# for: 1.050000 0.000000 1.050000 ( 0.503462) | |
# times: 1.533333 0.016667 1.550000 ( 0.735473) | |
# upto: 1.500000 0.016667 1.516667 ( 0.711239) | |
# | |
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. <tt>GC.start</tt> 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 | |
# | |
# <i>Generates:</i> | |
# | |
# Rehearsal ----------------------------------------- | |
# sort! 11.928000 0.010000 11.938000 ( 12.756000) | |
# sort 13.048000 0.020000 13.068000 ( 13.857000) | |
# ------------------------------- total: 25.006000sec | |
# | |
# user system total real | |
# sort! 12.959000 0.010000 12.969000 ( 13.793000) | |
# sort 12.007000 0.000000 12.007000 ( 12.791000) | |
# | |
# #bmbm yields a Benchmark::Job object and returns an array of | |
# Benchmark::Tms objects. | |
# | |
def bmbm(width = 0, &blk) # :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.to_f - r0.to_f, | |
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 |
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