SPUG: NYTProf for October 2010 meeting

Andrew Sweger andrew at sweger.net
Fri Oct 8 17:27:22 PDT 2010

Sounds great. You got my vote, though I probably won't make it.

Why y'all so quiet? Is NYTProf boring? It just saved my bacon today. I
threw some of my ugliest code at the latest version and it kindly pointed
out that some code was causing PL_sawampersand* to be set and where it was
probably happening. (I've been having trouble getting Devel::FindAmpersand
to work.)

* From Devel::SawAmpersand:

There's a global variable in the perl source, called PL_sawampersand. It
gets set to true in that moment in which the parser sees one of $`, $',
and $&. It never can be set to false again. Trying to set it to false
breaks the handling of the $`, $&, and $' completely.

If the global variable PL_sawampersand is set to true, all subsequent RE
operations will be accompanied by massive in-memory copying, because there
is nobody in the perl source who could predict, when the (necessary) copy
for the ampersand family will be needed. So all subsequent REs are
considerable slower than necessary.

On Fri, 8 Oct 2010, Augustina Blair wrote:

> I went to OSCON and saw a talk on NYTProf. I've been meaning to play
> around with it more and having to give a talk on it would be a good
> excuse to do so. So, I'm volunteering to give a talk on NYTProf for
> this month's SPUG, unless someone has something cooler or there's some
> awesome guest from out town that would rather present. I don't know
> how long my talk would be so we could easily couple this with another
> activity or another talk as far as I'm concerned.

Andrew B. Sweger -- The great thing about multitasking is that several
                                things can go wrong at once.

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