dPERINTERP/MY_CXT (was: speeding up XS_DBI_dispatch())

On Wed, Jan 25, 2012 at 05:37:13PM -0800, Jan Dubois wrote:
> On Wed, 25 Jan 2012, Tim Bunce wrote:
> > On Wed, Jan 25, 2012 at 04:14:07PM +0000, Dave Mitchell wrote:
> > 
> > > PS - I'm specifically being paid only to fix a performance issue on
> > > non-threaded builds, so I won't be looking at threaded issues. But
> > > dPERINTERP looks like bad news on threaded builds.
> > 
> > The dPERINTERP stuff was added by ActiveState years ago to support
> > MULTIPLICITY. I don't remember the details now. I do recall that driver
> > authors are encouraged to avoid using the DBIS macro due to the cost.
> > There's rarely a need now as DBI handles carry a pointer to the
> > dbi_state structure. The DBI::DBD docs say
> 
> Sorry, only skimming the conversation, so maybe this is obvious to
> you: PERINTERP was a prototype from the 5.005 days for the MY_CXT
> stuff that is now in the code. If you look at 5.8.1, then you'll see
> MY_CXT being almost identical to PERINTERP in DBI. But switching to
> MY_CXT should give you performance benefits on later Perl versions,
> which have an improved MY_CXT implementation.

Great. Thanks Jan.

Anyone want to take a shot at that?

Tim.