=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
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
=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<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 timeit(COUNT, CODE)
Arguments: COUNT is the number of times to run the loop, and CODE is
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
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( $results );
+
+Returns the data structure returned by timethese() (or passed in).
+
+=item countit(TIME, CODE)
+
+Arguments: TIME is the minimum length of time to run CODE for, and CODE is
+the code to run. CODE may be either a code reference or a string to
+be eval'd; either way it will be run in the caller's package.
+
+TIME is I<not> negative. countit() will run the loop many times to
+calculate the speed of CODE before running it for TIME. The actual
+time run for will usually be greater than TIME due to system clock
+resolution, so it's best to look at the number of iterations divided
+by the times that you are concerned with, not just the iterations.
+
+Returns: a Benchmark object.
+
=item disablecache ( )
Disable caching of timings for the null loop. This will force Benchmark
rounds of the null loop will be calculated only once for each
different COUNT used.
+=item timesum ( T1, T2 )
+
+Returns the sum of two Benchmark times as a Benchmark object suitable
+for passing to timestr().
+
=back
=head1 NOTES
Caching is off by default, as it can (usually slightly) decrease
accuracy and does not usually noticably affect runtimes.
+=head1 EXAMPLES
+
+For example,
+
+ use Benchmark;$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($r);
+
+outputs something like this:
+
+ Rate b a
+ b 1559428/s -- -62%
+ a 4152037/s 166% --
+
+
=head1 INHERITANCE
Benchmark inherits from no other class, except of course
more than the system time of the loop with the actual
code and therefore the difference might end up being E<lt> 0.
+=head1 SEE ALSO
+
+L<Devel::DProf> - a Perl code profiler
+
=head1 AUTHORS
Jarkko Hietaniemi <F<jhi@iki.fi>>, Tim Bunce <F<Tim.Bunce@ig.co.uk>>
use Carp;
use Exporter;
@ISA=(Exporter);
-@EXPORT=qw(cmpthese countit timeit timethis timethese timediff timestr);
-@EXPORT_OK=qw(clearcache clearallcache disablecache enablecache);
+@EXPORT=qw(timeit timethis timethese timediff timestr);
+@EXPORT_OK=qw(timesum cmpthese countit
+ clearcache clearallcache disablecache enablecache);
+
+$VERSION = 1.01;
&init;
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;
}
# 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);
# accuracy since we're not couting these times.
$n = int( $tpra * 1.05 * $n / $tc ); # Linear approximation.
my $td = timeit($n, $code);
- $tc = $td->[1] + $td->[2];
+ 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
$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;
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:
https://perl5.git.perl.org / perl5.git / blobdiff