[Python-Dev] seeing off SET_LINENO

[Guido van Rossum]

> Here goes.  Everything is relative to 221-base, which is 2.2.1 from Sean's 
> RPM.  This is the slowest, so all percentages are negative, and more 
> negative is better.  I hope the names are obvious.
> 
> 221-base             +0.00% (obviously)
> 221-O-base:          -9.69%
> CVS-base:           -15.43%
> CVS-O-base:         -23.56%
> CVS-hacked:         -23.66%
> CVS-O-hacked:       -23.70%
> 
> (Nearly 25% speed up since 221?  Boggle.  Some of this may be compilation 
> options, I guess)

No, pymalloc sped us up quite a bit.

> Anyway, it seems I haven't slowed -O down.  At some point I might try 
> moving the trace code out of line and see if that has any effect.  Not 
> today.

Fine.

> If you want to look at where the improvements are in more detail, I've put 
> the pybench files here:
> 
>     http://starship.python.net/crew/mwh/hacks/pybench-files.tar.gz
> 
> > (I guess the only difference that -O makes now is that asserts aren't
> > compiled. :-)
> 
> I think so, yes.

Ah well.  So much -O. :-)

> > > 9) This patch stops LLTRACE telling you when execution moves onto a
> > >    different line.  This could be restored, but
> > > 
> > >    a) I expect I'm the only persion to have used LLTRACE recently
> > >       (debugging this patch).
> > >    b) This will cause obfuscation, so I'd prefer to do it last.
> > > 
> > > No change here either.
> > 
> > I'm not too attached to LLTRACE.  As long as it's usable for debugging
> > massive changes to the VM implementation I'm okay with it.
> 
> Good.  I don't suppose you'd actually LLTRACE something without dis output 
> in front of you anyway, so this isn't much of a loss. Something I just 
> remembered: I turned off LLTRACE for trace functions.  I guess this isn't 
> really worth caring about either.

Fine.

What's the next step?  I haven't had time to review your code.  Do you
want to check it in without further review, or do you want to wait
until someone can give it a serious look?  (Tim's on vacation this
week so it might be a while.)

--Guido van Rossum (home page: http://www.python.org/~guido/)