++ed by:
PERLANCAR SHARYANTO KES

3 PAUSE users

Andrew Main (Zefram)

NAME

Devel::GoFaster - optimise executable Perl ops

SYNOPSIS

        use Devel::GoFaster;

        use Devel::GoFaster "global";

DESCRIPTION

This module implements some optimisations in compiled Perl code, which should make it run slightly faster without visibly affecting behaviour. The optimisations are applied at the peephole optimisation step, augmenting Perl's built-in optimisations.

Code to be made faster does not need to be written in any special way; this module can generally be applied to code that was not written with it in mind. However, to help with situations where the op munging causes trouble (such as with the deparser), there is some selectivity in which code gets the optimisations. Whether to apply these optimisations is decided for each subroutine as a whole: it cannot be enabled or disabled for just part of a subroutine. There is a global control, defaulting to off, and lexically-scoped local control which takes precedence over the global control.

Because the optimisations are applied in the peephole optimiser, not affecting primary compilation, they are invisible to most modules that muck around with op trees during compilation. So this module should play nicely with modules that use custom ops and the like. However, anything that examines the ops of a complete compiled subroutine is liable to see the non-standard optimised ops from this module, and may have a problem. In particular, the deparser can't correctly deparse code that has been affected by this module. If such problems affect a particular subroutine, the lexical control can be used to disable non-standard optimisation of that subroutine alone.

This module tries quite hard to not visibly fail, so that it should be generally safe to use its pragmata. If circumstances make it impossible to apply optimisations that would sometimes be available, the module will silently leave code unoptimised. In particular, because all the optimisations are necessarily implemented using XS code, on any system that can't build or load XS modules this module's pragmata effectively become no-ops. No particular optimisations are guaranteed by invoking this module.

PRAGMATA

use Devel::GoFaster

Locally enable the optimisations of this module. Subroutines compiled in the lexical scope of this pragma will get the non-standard optimisations, regardless of the global pragma state.

no Devel::GoFaster

Locally disable the optimisations of this module. Subroutines compiled in the lexical scope of this pragma will not get the non-standard optimisations, regardless of the global pragma state.

use Devel::GoFaster "global"

Globally enable the optimisations of this module. Subroutines compiled after this pragma has been encountered will get the non-standard optimisations, except where locally overridden.

no Devel::GoFaster "global"

Globally disable the optimisations of this module (which is the default state). Subroutines compiled after this pragma has been encountered will not get the non-standard optimisations, except where locally overridden.

BUGS

As noted above, this module is liable to break anything that examines the ops of a complete compiled subroutine, such as the deparser.

AUTHOR

Andrew Main (Zefram) <zefram@fysh.org>

COPYRIGHT

Copyright (C) 2015 Andrew Main (Zefram) <zefram@fysh.org>

LICENSE

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