package Dumbbench::Instance::Cmd;
use strict;
use warnings;
use Carp ();
use Time::HiRes ();
use Dumbbench::Instance;
use parent 'Dumbbench::Instance';
use Class::XSAccessor {
getters => [qw(
command
dry_run_command
)],
accessors => [qw(
use_shell
)],
};
=head1 NAME
Dumbbench::Instance::Cmd - Benchmarks an external command
=head1 SYNOPSIS
use Dumbbench;
my $bench = Dumbbench->new(
target_rel_precision => 0.005, # seek ~0.5%
initial_runs => 20, # the higher the more reliable
);
$bench->add_instances(
Dumbbench::Instance::Cmd->new(name => 'mauve', command => [qw(perl -e 'something')]),
# ... more things to benchmark ...
);
$bench->run();
# ...
=head1 DESCRIPTION
This class inherits from L<Dumbbench::Instance> and implements
benchmarking of external commands.
=head1 METHODS
=head2 new
Constructor that takes named arguments.
In addition to the properties of the base class, the
C<Dumbbench::Instance::Cmd> constructor requires a C<command>
parameter. C<command> can either be string specifying the
external command with its options or (preferably) a
reference to an array of command-name and options
(as with the ordinary C<system> builtin).
Optionally, you can provide a C<dry_run_command> option.
It has the same structure and purpose as the C<command>
option, but it is used for the dry-runs. If C<dry_run_command>
is not specified, the dry-run will consist of starting
another process that immediately exits.
=head2 command
Returns the command that was set on object construction.
=head2 dry_run_command
Returns the command that was set for dry-runs on object construction.
=cut
sub clone {
my $self = shift;
my $clone = $self->SUPER::clone(@_);
if (defined $self->command) {
$clone->{command} = [@{$self->command}];
}
return $clone;
}
sub single_run {
my $self = shift;
my @cmd = (ref($self->{command}) ? @{$self->{command}} : ($self->{command}));
@cmd = ("") if not @cmd;
#my $start;
#my $tbase = Time::HiRes::time();
#while ( ($start = Time::HiRes::time()) <= $tbase+1.e-15 ) {} # wait for clock tick. See discussion in Benchmark.pm comments
my ($start, $end);
if ($self->use_shell) {
my $cmd = join ' ', @cmd;
$start = Time::HiRes::time();
system($cmd);
$end = Time::HiRes::time();
}
else {
my $cmd = $cmd[0];
$start = Time::HiRes::time();
system({$cmd} @cmd);
$end = Time::HiRes::time();
}
my $duration = $end-$start;
return $duration;
}
sub single_dry_run {
my $self = shift;
my @cmd;
if (defined $self->{dry_run_command}) {
@cmd = (ref($self->{dry_run_command}) ? @{$self->{dry_run_command}} : ($self->{dry_run_command}));
}
else {
my @orig_cmd = (ref($self->{command}) ? @{$self->{command}} : ($self->{command}));
if (@orig_cmd and $orig_cmd[0] =~ /(?:^|\b)perl(?:\d+\.\d+\.\d+)?/) {
@cmd = ($orig_cmd[0], '-e', '1');
}
}
if (!@cmd) {
# FIXME For lack of a better dry run test, we always use perl for now as a fallback
@cmd = ($^X, qw(-e 1));
}
my ($start, $end);
if ($self->use_shell) {
my $cmd = join ' ', @cmd;
my $tbase = Time::HiRes::time();
while ( ($start = Time::HiRes::time()) <= $tbase+1.e-15 ) {} # wait for clock tick. See discussion in Benchmark.pm comments
system($cmd);
$end = Time::HiRes::time();
}
else {
my $cmd = $cmd[0];
my $tbase = Time::HiRes::time();
while ( ($start = Time::HiRes::time()) <= $tbase+1.e-15 ) {} # wait for clock tick. See discussion in Benchmark.pm comments
system({$cmd} @cmd);
$end = Time::HiRes::time();
}
my $duration = $end-$start;
return $duration;
}
1;
__END__
=head1 SEE ALSO
L<Dumbbench>, L<Dumbbench::Instance>,
L<Dumbbench::Instance::PerlEval>,
L<Dumbbench::Instance::PerlSub>,
L<Dumbbench::Result>
L<Benchmark>
L<Number::WithError> does the Gaussian error propagation.
L<SOOT> can optionally generate histograms from the
timing distributions.
L<http://en.wikipedia.org/wiki/Median_absolute_deviation>
=head1 AUTHOR
Steffen Mueller, E<lt>smueller@cpan.orgE<gt>
=head1 COPYRIGHT AND LICENSE
Copyright (C) 2010 by Steffen Mueller
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself, either Perl version 5.8.1 or,
at your option, any later version of Perl 5 you may have available.
=cut