X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FBenchmark.pm;h=3c10a5bc523b4e312f8c038e8869e7d83b053956;hb=8c99d73ee7ce90de2561496f683f3850d1269e1d;hp=a7debd73eec70d0460886ac958bfa4cef328771e;hpb=431d98c2031fccd9ea4057d71a9383bc5c187f4e;p=p5sagit%2Fp5-mst-13.2.git diff --git a/lib/Benchmark.pm b/lib/Benchmark.pm index a7debd7..3c10a5b 100644 --- a/lib/Benchmark.pm +++ b/lib/Benchmark.pm @@ -2,17 +2,7 @@ package Benchmark; =head1 NAME -Benchmark - benchmark running times of code - -timethis - run a chunk of code several times - -timethese - run several chunks of code several times - -cmpthese - print results of timethese as a comparison chart - -timeit - run a chunk of code and see how long it goes - -countit - see how many times a chunk of code runs in a given time +Benchmark - benchmark running times of Perl code =head1 SYNOPSIS @@ -63,6 +53,17 @@ countit - see how many times a chunk of code runs in a given time The Benchmark module encapsulates a number of routines to help you figure out how long it takes to execute some code. +timethis - run a chunk of code several times + +timethese - run several chunks of code several times + +cmpthese - print results of timethese as a comparison chart + +timeit - run a chunk of code and see how long it goes + +countit - see how many times a chunk of code runs in a given time + + =head2 Methods =over 10 @@ -99,34 +100,6 @@ if you use the Benchmark module: =over 10 -=item cmpthese ( COUT, CODEHASHREF, [ STYLE ] ) - -=item cmpthese ( RESULTSHASHREF ) - -Optionally calls timethese(), then outputs comparison chart. This -chart is sorted from slowest to highest, and shows the percent -speed difference between each pair of tests. Can also be passed -the data structure that timethese() returns: - - $results = timethese( .... ); - cmpthese( $results ); - -Returns the data structure returned by timethese(). - -=item countit(TIME, CODE) - -Arguments: TIME is the minimum length of time to run CODE for, and CODE is -the code to run. CODE may be either a code reference or a string to -be eval'd; either way it will be run in the caller's package. - -TIME is I negative. countit() will run the loop many times to -calculate the speed of CODE before running it for TIME. The actual -time run for will usually be greater than TIME due to system clock -resolution, so it's best to look at the number of iterations divided -by the times that you are concerned with, not just the iterations. - -Returns: a Benchmark object. - =item timeit(COUNT, CODE) Arguments: COUNT is the number of times to run the loop, and CODE is @@ -187,11 +160,6 @@ Returns a hash of Benchmark objects, keyed by name. Returns the difference between two Benchmark times as a Benchmark object suitable for passing to timestr(). -=item timesum ( T1, T2 ) - -Returns the sum of two Benchmark times as a Benchmark object suitable -for passing to timestr(). - =item timestr ( TIMEDIFF, [ STYLE, [ FORMAT ] ] ) Returns a string that formats the times in the TIMEDIFF object in @@ -226,6 +194,34 @@ Clear the cached time for COUNT rounds of the null loop. Clear all cached times. +=item cmpthese ( COUT, CODEHASHREF, [ STYLE ] ) + +=item cmpthese ( RESULTSHASHREF ) + +Optionally calls timethese(), then outputs comparison chart. This +chart is sorted from slowest to fastest, and shows the percent +speed difference between each pair of tests. Can also be passed +the data structure that timethese() returns: + + $results = timethese( .... ); + cmpthese( $results ); + +Returns the data structure returned by timethese() (or passed in). + +=item countit(TIME, CODE) + +Arguments: TIME is the minimum length of time to run CODE for, and CODE is +the code to run. CODE may be either a code reference or a string to +be eval'd; either way it will be run in the caller's package. + +TIME is I negative. countit() will run the loop many times to +calculate the speed of CODE before running it for TIME. The actual +time run for will usually be greater than TIME due to system clock +resolution, so it's best to look at the number of iterations divided +by the times that you are concerned with, not just the iterations. + +Returns: a Benchmark object. + =item disablecache ( ) Disable caching of timings for the null loop. This will force Benchmark @@ -237,6 +233,11 @@ Enable caching of timings for the null loop. The time taken for COUNT rounds of the null loop will be calculated only once for each different COUNT used. +=item timesum ( T1, T2 ) + +Returns the sum of two Benchmark times as a Benchmark object suitable +for passing to timestr(). + =back =head1 NOTES @@ -269,6 +270,35 @@ calls like these: Caching is off by default, as it can (usually slightly) decrease accuracy and does not usually noticably affect runtimes. +=head1 EXAMPLES + +For example, + + use Benchmark;$x=3;cmpthese(-5,{a=>sub{$x*$x},b=>sub{$x**2}}) + +outputs something like this: + + Benchmark: running a, b, each for at least 5 CPU seconds... + a: 10 wallclock secs ( 5.14 usr + 0.13 sys = 5.27 CPU) @ 3835055.60/s (n=20210743) + b: 5 wallclock secs ( 5.41 usr + 0.00 sys = 5.41 CPU) @ 1574944.92/s (n=8520452) + Rate b a + b 1574945/s -- -59% + a 3835056/s 144% -- + +while + + use Benchmark; + $x=3; + $r=timethese(-5,{a=>sub{$x*$x},b=>sub{$x**2}},'none'); + cmpthese($r); + +outputs something like this: + + Rate b a + b 1559428/s -- -62% + a 4152037/s 166% -- + + =head1 INHERITANCE Benchmark inherits from no other class, except of course @@ -293,6 +323,10 @@ The system time of the null loop might be slightly more than the system time of the loop with the actual code and therefore the difference might end up being E 0. +=head1 SEE ALSO + +L - a Perl code profiler + =head1 AUTHORS Jarkko Hietaniemi >, Tim Bunce > @@ -324,8 +358,11 @@ sub _doeval { eval shift } use Carp; use Exporter; @ISA=(Exporter); -@EXPORT=qw(cmpthese countit timeit timethis timethese timediff timestr); -@EXPORT_OK=qw(clearcache clearallcache disablecache enablecache); +@EXPORT=qw(timeit timethis timethese timediff timestr); +@EXPORT_OK=qw(timesum cmpthese countit + clearcache clearallcache disablecache enablecache); + +$VERSION = 1.00; &init; @@ -386,19 +423,19 @@ sub timestr { my @t = @$tr; warn "bad time value (@t)" unless @t==6; my($r, $pu, $ps, $cu, $cs, $n) = @t; - my($pt, $ct, $t) = ($tr->cpu_p, $tr->cpu_c, $tr->cpu_a); + my($pt, $ct, $tt) = ($tr->cpu_p, $tr->cpu_c, $tr->cpu_a); $f = $defaultfmt unless defined $f; # format a time in the required style, other formats may be added here $style ||= $defaultstyle; $style = ($ct>0) ? 'all' : 'noc' if $style eq 'auto'; my $s = "@t $style"; # default for unknown style $s=sprintf("%2d wallclock secs (%$f usr %$f sys + %$f cusr %$f csys = %$f CPU)", - @t,$t) if $style eq 'all'; + $r,$pu,$ps,$cu,$cs,$tt) if $style eq 'all'; $s=sprintf("%2d wallclock secs (%$f usr + %$f sys = %$f CPU)", $r,$pu,$ps,$pt) if $style eq 'noc'; $s=sprintf("%2d wallclock secs (%$f cusr + %$f csys = %$f CPU)", $r,$cu,$cs,$ct) if $style eq 'nop'; - $s .= sprintf(" @ %$f/s (n=$n)", $n / ( $pu + $ps )) if $n; + $s .= sprintf(" @ %$f/s (n=$n)", $n / ( $pu + $ps )) if $n && $pu+$ps; $s; } @@ -443,9 +480,7 @@ sub runloop { # in &countit. This, in turn, can reduce the number of calls to # &runloop a lot, and thus reduce additive errors. my $tbase = Benchmark->new(0)->[1]; - do { - $t0 = Benchmark->new(0); - } while ( $t0->[1] == $tbase ); + while ( ( $t0 = Benchmark->new(0) )->[1] == $tbase ) {} ; &$subref; $t1 = Benchmark->new($n); $td = &timediff($t1, $t0); @@ -728,7 +763,7 @@ sub cmpthese{ sort { $$a <=> $$b } map { \$_ } @col_widths[2..$#col_widths]; my $max_width = ${$sorted_width_refs[-1]}; - my $total = 0; + my $total = @col_widths - 1 ; for ( @col_widths ) { $total += $_ } STRETCHER: