[rescue] Sun 3/60

[Greg A. Woods]

[ On Thursday, August 16, 2001 at 15:47:30 (-0400), Dave McGuire wrote: ]
> Subject: Re: [rescue] Sun 3/60
>
>   General interactive performance.  Never got around to collecting
> actual numbers; the "feel" of X was so much better that we didn't
> bother.

Hmmm....

>   Just to be sure, we're talking about the stock cc that comes with
> SunOS4, not the extra-cost SunPro compiler, right?

Yes, just the stock 'cc'.

> Quote from X11R4 release notes:
> 
> 7.   If you are running on a VAX  or  680x0  processor,  you
>      should consider using the GNU C compiler (available via
>      anonymous ftp from the machine prep.ai.mit.edu) to com-
>      pile  the server.  It can result in up to a factor of 2
>      improvement in performance.  See the  HasGcc  parameter
>      in  the files sun.cf, ultrix.cf, macII.cf, and site.def
>      in mit/config/.

Ah, very interesting!

I've not got an X11R4 tree around any more -- in fact I don't think I've
run it for so long now that I can't even remember where I might have had
it last.

This smells very VERY much like custom hacking of the X11 code to tweak
it explicitly for GCC though -- if you have to turn on a flag like that.

I happened to check in the world.log file the last time I built X11R5 on
sun3 (1995, ~ 12 hours to build! :-)) and I see I built it with
'-f68881' and as I recall that made a very noticable difference both to
the feel of things as well as to x11perf...  I see I also used '-target
sun3', but I don't remember why.

I'm betting they did some early inlining experiments or some such.

I think it was about X11R4 when work by folks at the UofToronto to
improve code locality in the Xserver might have made it out to the
general release too.

It's interesting that this advice didn't make it into the X11R5 notes or
beyond (maybe they thought sun3 & vax were dead?).  I do note that in
X11R5 there are some farily specific compiler options enabled for GCC,
espeically on m68k and i386 platforms -- some apparently to work around
compiler differences but others to enable special optimisations.

>   If you actually want to do this, let me know...I'm interested in
> your results, and I might do it here as well for kicks.  I miss
> hacking on Sun3 systems.

It's not looking like it's going to cool down anytime soon, but I'll try
to remember!  ;-)

(right now my basement computer room is hovering around 80-85 at mid-day
on any sunny day, and that's with an 8,000 BTU AC blasting away in the
window!)

-- 
							Greg A. Woods

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