Re: Optimize PL/Perl function argument passing [PATCH]

On 01/15/2011 12:31 AM, Alex Hunsaker wrote:
> On Tue, Dec 7, 2010 at 07:24, Tim Bunce<Tim(dot)Bunce(at)pobox(dot)com> wrote:
>> Changes:
>>
>> Sets the local $_TD via C instead of passing an extra argument.
>> So functions no longer start with "our $_TD; local $_TD = shift;"
>>
>> Pre-extend stack for trigger arguments for slight performance gain.
>>
>> Passes installcheck.
> Cool, surprisingly in the non trigger case I saw up to an 18% speedup.
> The trigger case remained about the same, I suppose im I/O bound.
>
> Find attached a v2 with some minor fixes, If it looks good to you Ill
> mark this as "Ready for Commit".
>
> Changes:
> - move up a declaration to make it c90 safe
> - avoid using tg_trigger before it was initialized
> - only extend the stack to the size we need (there was + 1 which
> unless I am missing something was needed because we used to push $_TD
> on the stack, but we dont any more)
>

This looks pretty good. But why are we bothering to keep $prolog at all
any more, if all we're going to pass it is &PL_sv_no all the time? Maybe
we'll have a use for it in the future, but right now we don't appear to
unless I'm missing something.

cheers

andrew