Bench - Benchmark running times of Perl code


This document describes version 0.10 of Bench (from Perl distribution Bench), released on 2014-05-14.


 # time the whole program
 % perl -MBench -e'...'

 # basic usage of bench()
 % perl -MBench -e'bench sub { ... }'
 100 calls (58548/s), 0.0017s (0.0171ms/call)

 # get bench result in a variable
 % perl -MBench -E'my $res = bench sub { ... }'

 # specify bench options
 % perl -MBench -E'bench sub { ... }, 100'
 % perl -MBench -E'bench sub { ... }, {n=>-5}'
 304347 calls (60665/s), 5.017s (0.0165ms/call)

 # use Dumbbench as the backend
 % perl -MDumbbench -MBench -E'bench sub { ... }'
 % perl -MBench -E'bench sub { ... }, {dumbbench=>1, dumbbench_options=>{...}}'
 Ran 26 iterations (6 outliers).
 Rounded run time per iteration: 2.9029e-02 +/- 4.8e-05 (0.2%)

 # bench multiple codes
 % perl -MBench -E'bench {a=>sub{...}, b=>sub{...}}, {n=>-2}'
 % perl -MBench -E'bench [sub{...}, sub{...}]'; # automatically named a, b, ...
 b: 100 calls (5357/s), 0.0187s (0.1870ms/call)
 a: 100 calls (12120/s), 0.0083s (0.0825ms/call)
 Fastest is a (2.267x b)


This module is an alternative interface for Benchmark. It provides some nice defaults and a simpler interface. There is only one function, bench(), and it is exported by default. If bench() is never called, the whole program will be timed.

This module can utilize Dumbbench as the backend instead of Benchmark.


bench SUB(S)[, OPTS]

Run Perl code(s) and time it (them). Exported by default. SUB can be a coderef for specifying a single sub, or hashref/arrayref for specifying multiple subs.

Options are specified in hashref OPTS. Available options:

  • n => INT (default: 100)

    Run the code n times, or if negative, until at least n CPU seconds.

  • dumbbench => BOOL

    If 0, do not use Dumbbench even if it is available. If 1, require and use Dumbbench. If left undef, will use Dumbbench if it is already loaded.

  • dumbbench_options => HASHREF

    Options that will be passed to Dumbbench constructor, e.g. {target_rel_precision=>0.005, initial_runs=>20}.


bench, command-line interface for this module




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Source repository is at


Please report any bugs or feature requests on the bugtracker website

When submitting a bug or request, please include a test-file or a patch to an existing test-file that illustrates the bug or desired feature.


Steven Haryanto <>


This software is copyright (c) 2014 by Steven Haryanto.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.