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Diffstat (limited to 'contrib/perl5/lib/Benchmark.pm')
-rw-r--r-- | contrib/perl5/lib/Benchmark.pm | 798 |
1 files changed, 0 insertions, 798 deletions
diff --git a/contrib/perl5/lib/Benchmark.pm b/contrib/perl5/lib/Benchmark.pm deleted file mode 100644 index b557be3..0000000 --- a/contrib/perl5/lib/Benchmark.pm +++ /dev/null @@ -1,798 +0,0 @@ -package Benchmark; - -=head1 NAME - -Benchmark - benchmark running times of Perl code - -=head1 SYNOPSIS - - timethis ($count, "code"); - - # Use Perl code in strings... - timethese($count, { - 'Name1' => '...code1...', - 'Name2' => '...code2...', - }); - - # ... or use subroutine references. - timethese($count, { - 'Name1' => sub { ...code1... }, - 'Name2' => sub { ...code2... }, - }); - - # cmpthese can be used both ways as well - cmpthese($count, { - 'Name1' => '...code1...', - 'Name2' => '...code2...', - }); - - cmpthese($count, { - 'Name1' => sub { ...code1... }, - 'Name2' => sub { ...code2... }, - }); - - # ...or in two stages - $results = timethese($count, - { - 'Name1' => sub { ...code1... }, - 'Name2' => sub { ...code2... }, - }, - 'none' - ); - cmpthese( $results ) ; - - $t = timeit($count, '...other code...') - print "$count loops of other code took:",timestr($t),"\n"; - - $t = countit($time, '...other code...') - $count = $t->iters ; - print "$count loops of other code took:",timestr($t),"\n"; - -=head1 DESCRIPTION - -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 - -=item new - -Returns the current time. Example: - - use Benchmark; - $t0 = new Benchmark; - # ... your code here ... - $t1 = new Benchmark; - $td = timediff($t1, $t0); - print "the code took:",timestr($td),"\n"; - -=item debug - -Enables or disable debugging by setting the C<$Benchmark::Debug> flag: - - debug Benchmark 1; - $t = timeit(10, ' 5 ** $Global '); - debug Benchmark 0; - -=item iters - -Returns the number of iterations. - -=back - -=head2 Standard Exports - -The following routines will be exported into your namespace -if you use the Benchmark module: - -=over 10 - -=item timeit(COUNT, CODE) - -Arguments: COUNT is the number of times to run the loop, 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. - -Returns: a Benchmark object. - -=item timethis ( COUNT, CODE, [ TITLE, [ STYLE ]] ) - -Time COUNT iterations of CODE. CODE may be a string to eval or a -code reference; either way the CODE will run in the caller's package. -Results will be printed to STDOUT as TITLE followed by the times. -TITLE defaults to "timethis COUNT" if none is provided. STYLE -determines the format of the output, as described for timestr() below. - -The COUNT can be zero or negative: this means the I<minimum number of -CPU seconds> to run. A zero signifies the default of 3 seconds. For -example to run at least for 10 seconds: - - timethis(-10, $code) - -or to run two pieces of code tests for at least 3 seconds: - - timethese(0, { test1 => '...', test2 => '...'}) - -CPU seconds is, in UNIX terms, the user time plus the system time of -the process itself, as opposed to the real (wallclock) time and the -time spent by the child processes. Less than 0.1 seconds is not -accepted (-0.01 as the count, for example, will cause a fatal runtime -exception). - -Note that the CPU seconds is the B<minimum> time: CPU scheduling and -other operating system factors may complicate the attempt so that a -little bit more time is spent. The benchmark output will, however, -also tell the number of C<$code> runs/second, which should be a more -interesting number than the actually spent seconds. - -Returns a Benchmark object. - -=item timethese ( COUNT, CODEHASHREF, [ STYLE ] ) - -The CODEHASHREF is a reference to a hash containing names as keys -and either a string to eval or a code reference for each value. -For each (KEY, VALUE) pair in the CODEHASHREF, this routine will -call - - timethis(COUNT, VALUE, KEY, STYLE) - -The routines are called in string comparison order of KEY. - -The COUNT can be zero or negative, see timethis(). - -Returns a hash of Benchmark objects, keyed by name. - -=item timediff ( T1, T2 ) - -Returns the difference between 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 -the requested STYLE. TIMEDIFF is expected to be a Benchmark object -similar to that returned by timediff(). - -STYLE can be any of 'all', 'none', 'noc', 'nop' or 'auto'. 'all' shows -each of the 5 times available ('wallclock' time, user time, system time, -user time of children, and system time of children). 'noc' shows all -except the two children times. 'nop' shows only wallclock and the -two children times. 'auto' (the default) will act as 'all' unless -the children times are both zero, in which case it acts as 'noc'. -'none' prevents output. - -FORMAT is the L<printf(3)>-style format specifier (without the -leading '%') to use to print the times. It defaults to '5.2f'. - -=back - -=head2 Optional Exports - -The following routines will be exported into your namespace -if you specifically ask that they be imported: - -=over 10 - -=item clearcache ( COUNT ) - -Clear the cached time for COUNT rounds of the null loop. - -=item clearallcache ( ) - -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( $results ); - -Returns the data structure returned by timethese() (or passed in). - -=item countit(TIME, CODE) - -Arguments: TIME is the minimum length of time to run CODE for, and CODE is -the code to run. CODE may be either a code reference or a string to -be eval'd; either way it will be run in the caller's package. - -TIME is I<not> negative. countit() will run the loop many times to -calculate the speed of CODE before running it for TIME. The actual -time run for will usually be greater than TIME due to system clock -resolution, so it's best to look at the number of iterations divided -by the times that you are concerned with, not just the iterations. - -Returns: a Benchmark object. - -=item disablecache ( ) - -Disable caching of timings for the null loop. This will force Benchmark -to recalculate these timings for each new piece of code timed. - -=item enablecache ( ) - -Enable caching of timings for the null loop. The time taken for COUNT -rounds of the null loop will be calculated only once for each -different COUNT used. - -=item timesum ( T1, T2 ) - -Returns the sum of two Benchmark times as a Benchmark object suitable -for passing to timestr(). - -=back - -=head1 NOTES - -The data is stored as a list of values from the time and times -functions: - - ($real, $user, $system, $children_user, $children_system, $iters) - -in seconds for the whole loop (not divided by the number of rounds). - -The timing is done using time(3) and times(3). - -Code is executed in the caller's package. - -The time of the null loop (a loop with the same -number of rounds but empty loop body) is subtracted -from the time of the real loop. - -The null loop times can be cached, the key being the -number of rounds. The caching can be controlled using -calls like these: - - clearcache($key); - clearallcache(); - - disablecache(); - enablecache(); - -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($r); - -outputs something like this: - - Rate b a - b 1559428/s -- -62% - a 4152037/s 166% -- - - -=head1 INHERITANCE - -Benchmark inherits from no other class, except of course -for Exporter. - -=head1 CAVEATS - -Comparing eval'd strings with code references will give you -inaccurate results: a code reference will show a slightly slower -execution time than the equivalent eval'd string. - -The real time timing is done using time(2) and -the granularity is therefore only one second. - -Short tests may produce negative figures because perl -can appear to take longer to execute the empty loop -than a short test; try: - - timethis(100,'1'); - -The system time of the null loop might be slightly -more than the system time of the loop with the actual -code and therefore the difference might end up being E<lt> 0. - -=head1 SEE ALSO - -L<Devel::DProf> - a Perl code profiler - -=head1 AUTHORS - -Jarkko Hietaniemi <F<jhi@iki.fi>>, Tim Bunce <F<Tim.Bunce@ig.co.uk>> - -=head1 MODIFICATION HISTORY - -September 8th, 1994; by Tim Bunce. - -March 28th, 1997; by Hugo van der Sanden: added support for code -references and the already documented 'debug' method; revamped -documentation. - -April 04-07th, 1997: by Jarkko Hietaniemi, added the run-for-some-time -functionality. - -September, 1999; by Barrie Slaymaker: math fixes and accuracy and -efficiency tweaks. Added cmpthese(). A result is now returned from -timethese(). Exposed countit() (was runfor()). - -=cut - -# evaluate something in a clean lexical environment -sub _doeval { eval shift } - -# -# put any lexicals at file scope AFTER here -# - -use Carp; -use Exporter; -@ISA=(Exporter); -@EXPORT=qw(timeit timethis timethese timediff timestr); -@EXPORT_OK=qw(timesum cmpthese countit - clearcache clearallcache disablecache enablecache); - -$VERSION = 1.00; - -&init; - -sub init { - $debug = 0; - $min_count = 4; - $min_cpu = 0.4; - $defaultfmt = '5.2f'; - $defaultstyle = 'auto'; - # The cache can cause a slight loss of sys time accuracy. If a - # user does many tests (>10) with *very* large counts (>10000) - # or works on a very slow machine the cache may be useful. - &disablecache; - &clearallcache; -} - -sub debug { $debug = ($_[1] != 0); } - -# The cache needs two branches: 's' for strings and 'c' for code. The -# emtpy loop is different in these two cases. -sub clearcache { delete $cache{"$_[0]c"}; delete $cache{"$_[0]s"}; } -sub clearallcache { %cache = (); } -sub enablecache { $cache = 1; } -sub disablecache { $cache = 0; } - -# --- Functions to process the 'time' data type - -sub new { my @t = (time, times, @_ == 2 ? $_[1] : 0); - print "new=@t\n" if $debug; - bless \@t; } - -sub cpu_p { my($r,$pu,$ps,$cu,$cs) = @{$_[0]}; $pu+$ps ; } -sub cpu_c { my($r,$pu,$ps,$cu,$cs) = @{$_[0]}; $cu+$cs ; } -sub cpu_a { my($r,$pu,$ps,$cu,$cs) = @{$_[0]}; $pu+$ps+$cu+$cs ; } -sub real { my($r,$pu,$ps,$cu,$cs) = @{$_[0]}; $r ; } -sub iters { $_[0]->[5] ; } - -sub timediff { - my($a, $b) = @_; - my @r; - for (my $i=0; $i < @$a; ++$i) { - push(@r, $a->[$i] - $b->[$i]); - } - bless \@r; -} - -sub timesum { - my($a, $b) = @_; - my @r; - for (my $i=0; $i < @$a; ++$i) { - push(@r, $a->[$i] + $b->[$i]); - } - bless \@r; -} - -sub timestr { - my($tr, $style, $f) = @_; - my @t = @$tr; - warn "bad time value (@t)" unless @t==6; - my($r, $pu, $ps, $cu, $cs, $n) = @t; - my($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)", - $r,$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 && $pu+$ps; - $s; -} - -sub timedebug { - my($msg, $t) = @_; - print STDERR "$msg",timestr($t),"\n" if $debug; -} - -# --- Functions implementing low-level support for timing loops - -sub runloop { - my($n, $c) = @_; - - $n+=0; # force numeric now, so garbage won't creep into the eval - croak "negative loopcount $n" if $n<0; - confess "Usage: runloop(number, [string | coderef])" unless defined $c; - my($t0, $t1, $td); # before, after, difference - - # find package of caller so we can execute code there - my($curpack) = caller(0); - my($i, $pack)= 0; - while (($pack) = caller(++$i)) { - last if $pack ne $curpack; - } - - my ($subcode, $subref); - if (ref $c eq 'CODE') { - $subcode = "sub { for (1 .. $n) { local \$_; package $pack; &\$c; } }"; - $subref = eval $subcode; - } - else { - $subcode = "sub { for (1 .. $n) { local \$_; package $pack; $c;} }"; - $subref = _doeval($subcode); - } - croak "runloop unable to compile '$c': $@\ncode: $subcode\n" if $@; - print STDERR "runloop $n '$subcode'\n" if $debug; - - # Wait for the user timer to tick. This makes the error range more like - # -0.01, +0. If we don't wait, then it's more like -0.01, +0.01. This - # may not seem important, but it significantly reduces the chances of - # getting a too low initial $n in the initial, 'find the minimum' loop - # 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]; - while ( ( $t0 = Benchmark->new(0) )->[1] == $tbase ) {} ; - &$subref; - $t1 = Benchmark->new($n); - $td = &timediff($t1, $t0); - timedebug("runloop:",$td); - $td; -} - - -sub timeit { - my($n, $code) = @_; - my($wn, $wc, $wd); - - printf STDERR "timeit $n $code\n" if $debug; - my $cache_key = $n . ( ref( $code ) ? 'c' : 's' ); - if ($cache && exists $cache{$cache_key} ) { - $wn = $cache{$cache_key}; - } else { - $wn = &runloop($n, ref( $code ) ? sub { undef } : '' ); - # Can't let our baseline have any iterations, or they get subtracted - # out of the result. - $wn->[5] = 0; - $cache{$cache_key} = $wn; - } - - $wc = &runloop($n, $code); - - $wd = timediff($wc, $wn); - timedebug("timeit: ",$wc); - timedebug(" - ",$wn); - timedebug(" = ",$wd); - - $wd; -} - - -my $default_for = 3; -my $min_for = 0.1; - - -sub countit { - my ( $tmax, $code ) = @_; - - if ( not defined $tmax or $tmax == 0 ) { - $tmax = $default_for; - } elsif ( $tmax < 0 ) { - $tmax = -$tmax; - } - - die "countit($tmax, ...): timelimit cannot be less than $min_for.\n" - if $tmax < $min_for; - - my ($n, $tc); - - # First find the minimum $n that gives a significant timing. - for ($n = 1; ; $n *= 2 ) { - my $td = timeit($n, $code); - $tc = $td->[1] + $td->[2]; - last if $tc > 0.1; - } - - my $nmin = $n; - - # Get $n high enough that we can guess the final $n with some accuracy. - my $tpra = 0.1 * $tmax; # Target/time practice. - while ( $tc < $tpra ) { - # The 5% fudge is to keep us from iterating again all - # that often (this speeds overall responsiveness when $tmax is big - # and we guess a little low). This does not noticably affect - # accuracy since we're not couting these times. - $n = int( $tpra * 1.05 * $n / $tc ); # Linear approximation. - my $td = timeit($n, $code); - my $new_tc = $td->[1] + $td->[2]; - # Make sure we are making progress. - $tc = $new_tc > 1.2 * $tc ? $new_tc : 1.2 * $tc; - } - - # Now, do the 'for real' timing(s), repeating until we exceed - # the max. - my $ntot = 0; - my $rtot = 0; - my $utot = 0.0; - my $stot = 0.0; - my $cutot = 0.0; - my $cstot = 0.0; - my $ttot = 0.0; - - # The 5% fudge is because $n is often a few % low even for routines - # with stable times and avoiding extra timeit()s is nice for - # accuracy's sake. - $n = int( $n * ( 1.05 * $tmax / $tc ) ); - - while () { - my $td = timeit($n, $code); - $ntot += $n; - $rtot += $td->[0]; - $utot += $td->[1]; - $stot += $td->[2]; - $cutot += $td->[3]; - $cstot += $td->[4]; - $ttot = $utot + $stot; - last if $ttot >= $tmax; - - $ttot = 0.01 if $ttot < 0.01; - my $r = $tmax / $ttot - 1; # Linear approximation. - $n = int( $r * $ntot ); - $n = $nmin if $n < $nmin; - } - - return bless [ $rtot, $utot, $stot, $cutot, $cstot, $ntot ]; -} - -# --- Functions implementing high-level time-then-print utilities - -sub n_to_for { - my $n = shift; - return $n == 0 ? $default_for : $n < 0 ? -$n : undef; -} - -sub timethis{ - my($n, $code, $title, $style) = @_; - my($t, $for, $forn); - - if ( $n > 0 ) { - croak "non-integer loopcount $n, stopped" if int($n)<$n; - $t = timeit($n, $code); - $title = "timethis $n" unless defined $title; - } else { - $fort = n_to_for( $n ); - $t = countit( $fort, $code ); - $title = "timethis for $fort" unless defined $title; - $forn = $t->[-1]; - } - local $| = 1; - $style = "" unless defined $style; - printf("%10s: ", $title) unless $style eq 'none'; - print timestr($t, $style, $defaultfmt),"\n" unless $style eq 'none'; - - $n = $forn if defined $forn; - - # A conservative warning to spot very silly tests. - # Don't assume that your benchmark is ok simply because - # you don't get this warning! - print " (warning: too few iterations for a reliable count)\n" - if $n < $min_count - || ($t->real < 1 && $n < 1000) - || $t->cpu_a < $min_cpu; - $t; -} - -sub timethese{ - my($n, $alt, $style) = @_; - die "usage: timethese(count, { 'Name1'=>'code1', ... }\n" - unless ref $alt eq HASH; - my @names = sort keys %$alt; - $style = "" unless defined $style; - print "Benchmark: " unless $style eq 'none'; - if ( $n > 0 ) { - croak "non-integer loopcount $n, stopped" if int($n)<$n; - print "timing $n iterations of" unless $style eq 'none'; - } else { - print "running" unless $style eq 'none'; - } - print " ", join(', ',@names) unless $style eq 'none'; - unless ( $n > 0 ) { - my $for = n_to_for( $n ); - print ", each for at least $for CPU seconds" unless $style eq 'none'; - } - print "...\n" unless $style eq 'none'; - - # we could save the results in an array and produce a summary here - # sum, min, max, avg etc etc - my %results; - foreach my $name (@names) { - $results{$name} = timethis ($n, $alt -> {$name}, $name, $style); - } - - return \%results; -} - -sub cmpthese{ - my $results = ref $_[0] ? $_[0] : timethese( @_ ); - - return $results - if defined $_[2] && $_[2] eq 'none'; - - # Flatten in to an array of arrays with the name as the first field - my @vals = map{ [ $_, @{$results->{$_}} ] } keys %$results; - - for (@vals) { - # The epsilon fudge here is to prevent div by 0. Since clock - # resolutions are much larger, it's below the noise floor. - my $rate = $_->[6] / ( $_->[2] + $_->[3] + 0.000000000000001 ); - $_->[7] = $rate; - } - - # Sort by rate - @vals = sort { $a->[7] <=> $b->[7] } @vals; - - # If more than half of the rates are greater than one... - my $display_as_rate = $vals[$#vals>>1]->[7] > 1; - - my @rows; - my @col_widths; - - my @top_row = ( - '', - $display_as_rate ? 'Rate' : 's/iter', - map { $_->[0] } @vals - ); - - push @rows, \@top_row; - @col_widths = map { length( $_ ) } @top_row; - - # Build the data rows - # We leave the last column in even though it never has any data. Perhaps - # it should go away. Also, perhaps a style for a single column of - # percentages might be nice. - for my $row_val ( @vals ) { - my @row; - - # Column 0 = test name - push @row, $row_val->[0]; - $col_widths[0] = length( $row_val->[0] ) - if length( $row_val->[0] ) > $col_widths[0]; - - # Column 1 = performance - my $row_rate = $row_val->[7]; - - # We assume that we'll never get a 0 rate. - my $a = $display_as_rate ? $row_rate : 1 / $row_rate; - - # Only give a few decimal places before switching to sci. notation, - # since the results aren't usually that accurate anyway. - my $format = - $a >= 100 ? - "%0.0f" : - $a >= 10 ? - "%0.1f" : - $a >= 1 ? - "%0.2f" : - $a >= 0.1 ? - "%0.3f" : - "%0.2e"; - - $format .= "/s" - if $display_as_rate; - # Using $b here due to optimizing bug in _58 through _61 - my $b = sprintf( $format, $a ); - push @row, $b; - $col_widths[1] = length( $b ) - if length( $b ) > $col_widths[1]; - - # Columns 2..N = performance ratios - my $skip_rest = 0; - for ( my $col_num = 0 ; $col_num < @vals ; ++$col_num ) { - my $col_val = $vals[$col_num]; - my $out; - if ( $skip_rest ) { - $out = ''; - } - elsif ( $col_val->[0] eq $row_val->[0] ) { - $out = "--"; - # $skip_rest = 1; - } - else { - my $col_rate = $col_val->[7]; - $out = sprintf( "%.0f%%", 100*$row_rate/$col_rate - 100 ); - } - push @row, $out; - $col_widths[$col_num+2] = length( $out ) - if length( $out ) > $col_widths[$col_num+2]; - - # A little wierdness to set the first column width properly - $col_widths[$col_num+2] = length( $col_val->[0] ) - if length( $col_val->[0] ) > $col_widths[$col_num+2]; - } - push @rows, \@row; - } - - # Equalize column widths in the chart as much as possible without - # exceeding 80 characters. This does not use or affect cols 0 or 1. - my @sorted_width_refs = - sort { $$a <=> $$b } map { \$_ } @col_widths[2..$#col_widths]; - my $max_width = ${$sorted_width_refs[-1]}; - - my $total = @col_widths - 1 ; - for ( @col_widths ) { $total += $_ } - - STRETCHER: - while ( $total < 80 ) { - my $min_width = ${$sorted_width_refs[0]}; - last - if $min_width == $max_width; - for ( @sorted_width_refs ) { - last - if $$_ > $min_width; - ++$$_; - ++$total; - last STRETCHER - if $total >= 80; - } - } - - # Dump the output - my $format = join( ' ', map { "%${_}s" } @col_widths ) . "\n"; - substr( $format, 1, 0 ) = '-'; - for ( @rows ) { - printf $format, @$_; - } - - return $results; -} - - -1; |