why gcc-3.1?

Albert Wagner alwagner at tcac.net
Mon May 27 08:49:52 PDT 2002


On Monday 27 May 2002 06:05 am, you wrote:
> Am Montag, 27. Mai 2002 06:37 schrieben Sie:
> > Other than just being first-on-the-block, what are the advantages of
> > gcc-3.1 over gcc-2.95.3?
<snip>
> > Sounds spooky to me.
>
> Why?

Because I don't see the advantages.  The main question of my post was a 
request for a summary of discussed advantages.  It's spooky because I haven't 
yet seen any such list.

<snip>

> > What about those of us who don't know how to turn a compile error into a
> > patch and yet find ourselves needing packages that no one here has any
> > need for or experience with?
>
> I guess that all actively maintained projects will make their source
> compile with gcc-3.1 sooner or later, i suppose it will be sooner...

This is a good reason to be spooky.  I would prefer something more than just 
supposing sooner or later.

>
> And by the way you are by no means forced to use the same compiler as
> the book does. Just stick with 2.95.3 if it is more to your liking.

That means, of course, staying with 3.3.  The patches to the other packages 
in a new book won't work with 2.95.3.

>
> I use gcc-3.1 exclusively since the day it come out and i think its
> great, "-O3 -march=athlon-mp" anyone?

Same question:  Why do you think it's great.

>
> I also postulate (of course without any authority and with just a
> single test i ran) that gcc-3.1 gives better performance.
> I did the following in my usual working environment on always
>
> the same machine, with BLFS systems build using gcc-2.95.3 and 3.1:
> :> time bzip2 mozilla.tar (mozilla.tar beeing about 250MB)
>
> Thats what i got:
>
> 1 .) gcc-2.95.3: -O3 -march=i686 :
>      209.47 user
>      1.18 system
>      3:30.77 elapsed
>      99%CPU
> 2 .) gcc-3.1: -O3 -march=i686:
>      197.82user
>      1.87system
>      3:20.94elapsed
>      99%CPU
> 3 .) gcc-3.1: -O3 -march=athlon-mp:
>      190.04user
>      0.91system
>      3:10.95elapsed
>      99%CPU
>
> About 10% better performance from 1.) to 3.) !

Assuming that this is more than just anecdotal, is a 10%  savings in compile 
time worth the hassle.  Surely, there is more.

>
> Michael

-- 
Quantum Mechanics: The dreams stuff is made of
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