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... },
+ });
+
$t = timeit($count, '...other code...')
print "$count loops of other code took:",timestr($t),"\n";
# ... your code here ...
$t1 = new Benchmark;
$td = timediff($t1, $t0);
- print "the code took:",timestr($dt),"\n";
+ print "the code took:",timestr($td),"\n";
=item debug
Enables or disable debugging by setting the C<$Benchmark::Debug> flag:
- debug Benchmark 1;
+ debug Benchmark 1;
$t = timeit(10, ' 5 ** $Global ');
- debug Benchmark 0;
+ debug Benchmark 0;
=back
=head2 Standard Exports
-The following routines will be exported into your namespace
+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 time to run the loop, and
-the second is the code to run. CODE may be a string containing the code,
-a reference to the function to run, or a reference to a hash containing
-keys which are names and values which are more CODE specs.
+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 ] )
-Side-effects: prints out noise to standard out.
+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
-Returns: a Benchmark object.
+ timethis(COUNT, VALUE, KEY, STYLE)
-=item timethis
+The routines are called in string comparison order of KEY.
-=item timethese
+The COUNT can be zero or negative, see timethis().
-=item timediff
+=item timediff ( T1, T2 )
-=item timestr
+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', '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'.
+
+FORMAT is the L<printf(3)>-style format specifier (without the
+leading '%') to use to print the times. It defaults to '5.2f'.
=back
=over 10
-clearcache
+=item clearcache ( COUNT )
+
+Clear the cached time for COUNT rounds of the null loop.
+
+=item clearallcache ( )
+
+Clear all cached times.
+
+=item disablecache ( )
-clearallcache
+Disable caching of timings for the null loop. This will force Benchmark
+to recalculate these timings for each new piece of code timed.
-disablecache
+=item enablecache ( )
-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.
=back
=head1 NOTES
The data is stored as a list of values from the time and times
-functions:
+functions:
($real, $user, $system, $children_user, $children_system)
Code is executed in the caller's package.
-Enable debugging by:
-
- $Benchmark::debug = 1;
-
The time of the null loop (a loop with the same
number of rounds but empty loop body) is subtracted
from the time of the real loop.
number of rounds. The caching can be controlled using
calls like these:
- clearcache($key);
+ clearcache($key);
clearallcache();
- disablecache();
+ disablecache();
enablecache();
=head1 INHERITANCE
=head1 CAVEATS
+Comparing eval'd strings with code references will give you
+inaccurate results: a code reference will show a slower
+execution time than the equivalent eval'd string.
+
The real time timing is done using time(2) and
the granularity is therefore only one second.
Short tests may produce negative figures because perl
-can appear to take longer to execute the empty loop
-than a short test; try:
+can appear to take longer to execute the empty loop
+than a short test; try:
timethis(100,'1');
The system time of the null loop might be slightly
more than the system time of the loop with the actual
-code and therefore the difference might end up being < 0.
-
-More documentation is needed :-( especially for styles and formats.
+code and therefore the difference might end up being E<lt> 0.
=head1 AUTHORS
-Jarkko Hietaniemi <Jarkko.Hietaniemi@hut.fi>,
-Tim Bunce <Tim.Bunce@ig.co.uk>
+Jarkko Hietaniemi <F<jhi@iki.fi>>, Tim Bunce <F<Tim.Bunce@ig.co.uk>>
=head1 MODIFICATION HISTORY
September 8th, 1994; by Tim Bunce.
-=cut
+March 28th, 1997; by Hugo van der Sanden: added support for code
+references and the already documented 'debug' method; revamped
+documentation.
+
+April 04-07th, 1997: by Jarkko Hietaniemi, added the run-for-some-time
+functionality.
-# Purpose: benchmark running times of code.
-#
-#
-# Usage - to time code snippets and print results:
-#
-# timethis($count, '...code...');
-#
-# prints:
-# timethis 100: 2 secs ( 0.23 usr 0.10 sys = 0.33 cpu)
-#
-#
-# timethese($count, {
-# Name1 => '...code1...',
-# Name2 => '...code2...',
-# ... });
-# prints:
-# Benchmark: timing 100 iterations of Name1, Name2...
-# Name1: 2 secs ( 0.50 usr 0.00 sys = 0.50 cpu)
-# Name2: 1 secs ( 0.48 usr 0.00 sys = 0.48 cpu)
-#
-# The default display style will automatically add child process
-# values if non-zero.
-#
-#
-# Usage - to time sections of your own code:
-#
-# use Benchmark;
-# $t0 = new Benchmark;
-# ... your code here ...
-# $t1 = new Benchmark;
-# $td = &timediff($t1, $t0);
-# print "the code took:",timestr($td),"\n";
-#
-# $t = &timeit($count, '...other code...')
-# print "$count loops of other code took:",timestr($t),"\n";
-#
-#
-# Data format:
-# The data is stored as a list of values from the time and times
-# functions: ($real, $user, $system, $children_user, $children_system)
-# in seconds for the whole loop (not divided by the number of rounds).
-#
-# Internals:
-# The timing is done using time(3) and times(3).
-#
-# Code is executed in the callers package
-#
-# Enable debugging by: $Benchmark::debug = 1;
-#
-# The time of the null loop (a loop with the same
-# number of rounds but empty loop body) is substracted
-# from the time of the real loop.
-#
-# The null loop times are cached, the key being the
-# number of rounds. The caching can be controlled using
-# &clearcache($key); &clearallcache;
-# &disablecache; &enablecache;
-#
-# Caveats:
-#
-# 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 < 0
-#
-# More documentation is needed :-(
-# Especially for styles and formats.
-#
-# Authors: Jarkko Hietaniemi <Jarkko.Hietaniemi@hut.fi>
-# Tim Bunce <Tim.Bunce@ig.co.uk>
-#
-#
-# Last updated: Sept 8th 94 by Tim Bunce
-#
+=cut
+use Carp;
use Exporter;
@ISA=(Exporter);
@EXPORT=qw(timeit timethis timethese timediff timestr);
&clearallcache;
}
+sub debug { $debug = ($_[1] != 0); }
+
sub clearcache { delete $cache{$_[0]}; }
sub clearallcache { %cache = (); }
sub enablecache { $cache = 1; }
sub disablecache { $cache = 0; }
-
# --- Functions to process the 'time' data type
-sub new { my(@t)=(time, times); print "new=@t\n" if $debug; bless \@t; }
+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]}; $r ; }
-sub timediff{
+sub timediff {
my($a, $b) = @_;
- my(@r);
- for($i=0; $i < @$a; ++$i){
+ my @r;
+ for ($i=0; $i < @$a; ++$i) {
push(@r, $a->[$i] - $b->[$i]);
}
bless \@r;
}
-sub timestr{
+sub timestr {
my($tr, $style, $f) = @_;
- my(@t) = @$tr;
- warn "bad time value" unless @t==5;
- my($r, $pu, $ps, $cu, $cs) = @t;
+ my @t = @$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);
- $f = $defaultfmt unless $f;
+ $f = $defaultfmt unless defined $f;
# format a time in the required style, other formats may be added here
- $style = $defaultstyle unless $style;
- $style = ($ct>0) ? 'all' : 'noc' if $style=~/^auto$/;
- my($s) = "@t $style"; # default for unknown style
- $s=sprintf("%2d secs (%$f usr %$f sys + %$f cusr %$f csys = %$f cpu)",
- @t,$t) if $style =~ /^all$/;
- $s=sprintf("%2d secs (%$f usr %$f sys = %$f cpu)",
- $r,$pu,$ps,$pt) if $style =~ /^noc$/;
- $s=sprintf("%2d secs (%$f cusr %$f csys = %$f cpu)",
- $r,$cu,$cs,$ct) if $style =~ /^nop$/;
+ $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';
+ $s=sprintf("%2d wallclock secs (%$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;
$s;
}
-sub timedebug{
+
+sub timedebug {
my($msg, $t) = @_;
- print STDERR "$msg",timestr($t),"\n" if ($debug);
+ 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, $pack)= 0;
+ my($curpack) = caller(0);
+ my($i, $pack)= 0;
while (($pack) = caller(++$i)) {
last if $pack ne $curpack;
}
- my $subcode = "sub { package $pack; my(\$_i)=$n; while (\$_i--){$c;} }";
+ my $subcode = (ref $c eq 'CODE')
+ ? "sub { package $pack; my(\$_i)=$n; while (\$_i--){&\$c;} }"
+ : "sub { package $pack; my(\$_i)=$n; while (\$_i--){$c;} }";
my $subref = eval $subcode;
- die "runloop unable to compile '$c': $@\ncode: $subcode\n" if $@;
- print STDERR "runloop $n '$subcode'\n" if ($debug);
+ croak "runloop unable to compile '$c': $@\ncode: $subcode\n" if $@;
+ print STDERR "runloop $n '$subcode'\n" if $debug;
- $t0 = &new;
+ $t0 = Benchmark->new(0);
&$subref;
- $t1 = &new;
+ $t1 = Benchmark->new($n);
$td = &timediff($t1, $t0);
timedebug("runloop:",$td);
printf STDERR "timeit $n $code\n" if $debug;
- if ($cache && exists $cache{$n}){
+ if ($cache && exists $cache{$n}) {
$wn = $cache{$n};
- }else{
+ } else {
$wn = &runloop($n, '');
$cache{$n} = $wn;
}
}
+my $default_for = 3;
+my $min_for = 0.1;
+
+sub runfor {
+ my ($code, $tmax) = @_;
+
+ if ( not defined $tmax or $tmax == 0 ) {
+ $tmax = $default_for;
+ } elsif ( $tmax < 0 ) {
+ $tmax = -$tmax;
+ }
+
+ die "runfor(..., $tmax): timelimit cannot be less than $min_for.\n"
+ if $tmax < $min_for;
+
+ my ($n, $td, $tc, $ntot, $rtot, $utot, $stot, $cutot, $cstot );
+
+ # First find the minimum $n that gives a non-zero timing.
+
+ my $nmin;
+
+ for ($n = 1, $tc = 0; $tc <= 0; $n *= 2 ) {
+ $td = timeit($n, $code);
+ $tc = $td->[1] + $td->[2];
+ }
+
+ $nmin = $n;
+
+ my $ttot = 0;
+ my $tpra = 0.05 * $tmax; # Target/time practice.
+
+ # Double $n until we have think we have practiced enough.
+ for ( $n = 1; $ttot < $tpra; $n *= 2 ) {
+ $td = timeit($n, $code);
+ $tc = $td->cpu_p;
+ $ntot += $n;
+ $rtot += $td->[0];
+ $utot += $td->[1];
+ $stot += $td->[2];
+ $ttot = $utot + $stot;
+ $cutot += $td->[3];
+ $cstot += $td->[4];
+ }
+
+ my $r;
+
+ # Then iterate towards the $tmax.
+ while ( $ttot < $tmax ) {
+ $r = $tmax / $ttot - 1; # Linear approximation.
+ $n = int( $r * $n );
+ $n = $nmin if $n < $nmin;
+ $td = timeit($n, $code);
+ $ntot += $n;
+ $rtot += $td->[0];
+ $utot += $td->[1];
+ $stot += $td->[2];
+ $ttot = $utot + $stot;
+ $cutot += $td->[3];
+ $cstot += $td->[4];
+ }
+
+ 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) = timeit($n, $code);
- local($|) = 1;
- $title = "timethis $n" unless $title;
- $style = "" unless $style;
+ my($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 );
+ $t = runfor($code, $fort);
+ $title = "timethis for $fort" unless defined $title;
+ $forn = $t->[-1];
+ }
+ local $| = 1;
+ $style = "" unless defined $style;
printf("%10s: ", $title);
- print timestr($t, $style),"\n";
+ print timestr($t, $style, $defaultfmt),"\n";
+
+ $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
+ if $n < $min_count
|| ($t->real < 1 && $n < 1000)
- || $t->cpu_a < $min_cpu);
+ || $t->cpu_a < $min_cpu;
$t;
}
-
sub timethese{
my($n, $alt, $style) = @_;
die "usage: timethese(count, { 'Name1'=>'code1', ... }\n"
unless ref $alt eq HASH;
- my(@all);
- my(@names) = sort keys %$alt;
- $style = "" unless $style;
- print "Benchmark: timing $n iterations of ",join(', ',@names),"...\n";
- foreach(@names){
- $t = timethis($n, $alt->{$_}, $_, $style);
- push(@all, $t);
+ my @names = sort keys %$alt;
+ $style = "" unless defined $style;
+ print "Benchmark: ";
+ if ( $n > 0 ) {
+ croak "non-integer loopcount $n, stopped" if int($n)<$n;
+ print "timing $n iterations of";
+ } else {
+ print "running";
+ }
+ print " ", join(', ',@names);
+ unless ( $n > 0 ) {
+ my $for = n_to_for( $n );
+ print ", each for at least $for CPU seconds";
}
- # we could produce a summary from @all here
+ print "...\n";
+
+ # we could save the results in an array and produce a summary here
# sum, min, max, avg etc etc
- @all;
+ foreach my $name (@names) {
+ timethis ($n, $alt -> {$name}, $name, $style);
+ }
}
-
1;
projects / p5sagit/p5-mst-13.2.git / blobdiff