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=begin
#
# benchmark.rb - a performance benchmarking library
#
# $Id: benchmark.rb 11708 2007-02-12 23:01:19Z shyouhei $
#
# Created by Gotoken (gotoken@notwork.org).
#
# Documentation by Gotoken (original RD), Lyle Johnson (RDoc conversion), and
# Gavin Sinclair (editing).
#
=end
# == 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
# <tt>"a"*1_000_000</tt>:
#
# require 'benchmark'
#
# puts Benchmark.measure { "a"*1_000_000 }
#
# On my machine (FreeBSD 3.2 on P5, 100MHz) this generates:
#
# 1.166667 0.050000 1.216667 ( 0.571355)
#
# 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 = 50000
# 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
# 1.033333 0.016667 1.016667 ( 0.492106)
# 1.483333 0.000000 1.483333 ( 0.694605)
# 1.516667 0.000000 1.516667 ( 0.711077)
#
# * Continuing the previous example, put a label in each report:
#
# 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
#
# The result:
#
# 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)
#
#
# * 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! 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)
#
#
# * Report statistics of sequential experiments with unique labels,
# using the #benchmark method:
#
# require 'benchmark'
#
# n = 50000
# Benchmark.benchmark(" "*7 + CAPTION, 7, FMTSTR, ">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: 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)
module Benchmark
BENCHMARK_VERSION = "2002-04-25" # :nodoc:
def Benchmark.times # :nodoc:
Process.times
end
# 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 _fmt_ to format each line.
# 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 FMTSTR constants
#
# n = 50000
# Benchmark.benchmark(" "*7 + CAPTION, 7, FMTSTR, ">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, fmtstr=nil, *labels) # :yield: report
raise ArgumentError, "no block" unless block_given?
# swap
sync, STDOUT.sync = STDOUT.sync, true
label_width ||= 0
fmtstr ||= FMTSTR
print caption
results = yield(Report.new(label_width, fmtstr))
if Array === results
results.grep(Tms).each do |t|
lbl = labels.shift || t.label || ""
print lbl.ljust(label_width), t.format(fmtstr)
end
end
STDOUT.sync = sync
results
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 " " * label_width + CAPTION, label_width, FMTSTR, *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
sync, STDOUT.sync = STDOUT.sync, true
# rehearsal
print "Rehearsal "
puts '-' * (width+CAPTION.length - "Rehearsal ".length)
list = []
job.list.each do |label_item|
label, item = label_item
print label.ljust(width)
res = Benchmark.measure(label, &item)
print res.format
list.push res
end
sum = Tms.new; list.each{ |i| sum += i }
ets = sum.format("total: %tsec")
printf "%s %s\n\n", "-"*(width+CAPTION.length-ets.length-1), ets
# take
print ' ' * width, CAPTION
list = []
ary = []
job.list.each do |label_item|
label, item = label_item
GC.start
print label.ljust(width)
res = Benchmark.measure(label, &item)
print res.format
ary.push res
list.push [label, res]
end
STDOUT.sync = sync
ary
end
#
# Returns the time used to execute the given block as a
# Benchmark::Tms object.
#
def measure(label="") # :yield:
t0, r0 = Benchmark.times, Time.now
yield
t1, r1 = Benchmark.times, Time.now
Benchmark::Tms.new(t1.tutime - t0.tutime,
t1.tstime - t0.tstime,
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(&blk) # :yield:
Benchmark.measure(&blk).real
end
#
# 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 ArgmentError, "no block" unless block_given?
label.concat ' '
w = label.length
@width = w if @width < w
@list.push [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, plus one.
attr_reader :width
end
module_function :benchmark, :measure, :realtime, :bm, :bmbm
#
# 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 _fmtstr_ are the label offset and
# format string used by Tms#format.
#
def initialize(width=0, fmtstr=nil)
@width, @fmtstr = width, fmtstr
end
#
# Prints the _label_ and measured time for the block,
# formatted by _fmt_. See Tms#format for the
# formatting rules.
#
def item(label="", *fmt, &blk) # :yield:
print label.ljust(@width)
res = Benchmark.measure(label, &blk)
print res.format(@fmtstr, *fmt)
res
end
alias report item
end
#
# A data object, representing the times associated with a benchmark
# measurement.
#
class Tms
CAPTION = " user system total real\n"
FMTSTR = "%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
# _u_ as the user CPU time, _s_ as the system CPU time,
# _cu_ as the children's user CPU time, _cs_ as the children's
# system CPU time, _real_ as the elapsed real time and _l_
# as the label.
#
def initialize(u=0.0, s=0.0, cu=0.0, cs=0.0, real=0.0, l=nil)
@utime, @stime, @cutime, @cstime, @real, @label = u, s, cu, cs, real, l
@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 _fmtstr_ is not given, FMTSTR is used as default value, detailing the
# user, system and real elapsed time.
#
def format(arg0=nil, *args)
fmtstr = (arg0 || FMTSTR).dup
fmtstr.gsub!(/(%[-+\.\d]*)n/) { "#{$1}s" % label }
fmtstr.gsub!(/(%[-+\.\d]*)u/) { "#{$1}f" % utime }
fmtstr.gsub!(/(%[-+\.\d]*)y/) { "#{$1}f" % stime }
fmtstr.gsub!(/(%[-+\.\d]*)U/) { "#{$1}f" % cutime }
fmtstr.gsub!(/(%[-+\.\d]*)Y/) { "#{$1}f" % cstime }
fmtstr.gsub!(/(%[-+\.\d]*)t/) { "#{$1}f" % total }
fmtstr.gsub!(/(%[-+\.\d]*)r/) { "(#{$1}f)" % real }
arg0 ? Kernel.format(fmtstr, *args) : fmtstr
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
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.
FMTSTR = Benchmark::Tms::FMTSTR
end
if __FILE__ == $0
include Benchmark
n = ARGV[0].to_i.nonzero? || 50000
puts %Q([#{n} times iterations of `a = "1"'])
benchmark(" " + CAPTION, 7, FMTSTR) do |x|
x.report("for:") {for i in 1..n; a = "1"; end} # Benchmark.measure
x.report("times:") {n.times do ; a = "1"; end}
x.report("upto:") {1.upto(n) do ; a = "1"; end}
end
benchmark do
[
measure{for i in 1..n; a = "1"; end}, # Benchmark.measure
measure{n.times do ; a = "1"; end},
measure{1.upto(n) do ; a = "1"; end}
]
end
end
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