Re: PCL speedups.

[Arun Welch <welch@cis.ohio-state.edu>]

    I assume that (outside of the lap generation) the areas were
    performance tuning is possible are related to cache filling. 
    Currently have not looked at efficiency notes or compiled anything
    unsafe.  Are there particular files that have most of the important
    run-time code?  I would guess: cache, vector and methods.

Methods doesn't really have much of the stuff you want to diddle with in
it. Cache, and vector are the ones.

Oh yeah, another issue: the code-walker and iterate.  The walker is
probably the most bummed code in the package, having decended from
Masinter's Interlisp code-walker, which was heavily bummed there. It's
not worth spending much time trying to speed it up. Iterate actually
produces very clean code too, especially for complex iterations.  If
your loop macro expansion is very good, then it's worth replacing it,
otherwise not. I wrote some pretty hairy iterations using both our
ISOPRS (the generalised iteration facility in Interlisp, another heavily
bummed piece of code, explicitely for our architecture) and in the
Iterate package, and in most cases the iterate code was faster or the
same speed.  I believe Foderaro chose to hand-tune the iteration and
dumped the code walker and iterate for Allegro, since I can't find any
references to the symbols in it in 4.1 and they've got their own code
walker. In our case the PCL code walker was close enough to our existing
code walker, having derived from it and being only 2 function calls and
a free variable lookup different that I'm simply replacing the old one.

Speaking of Foderaro, he might be another person to talk to about it,
since he ported PCL too for Allegro. On the other hand, if he see's you
folks as a competitor (I know some folks at Franz do, dunno about him in
particular) then he might not be willing to talk. JonL's also worth
talking to even though he did theirs from scratch, and he helped me a
bunch so I doubt he'd have problems talking to you. 

    b.t.w. Sheila is still interested in the Mystery Science
    Theater tape, and is feeling guilty about having never called you
    back after your call at the end of last term...

No sweat.  I've got a half-dozen tapes of the show now, I'll select the
best ones.  Let me know when you want them.

...arun