gcc 3.1 and 10.2

brendon

It is known that Apple is right now making many changes to the gcc compiler to optimize for PowerPC processors. The last time that Apple had a really good compiler that they used 'MrC' they also had really good FP performance. Apple used the MrC compiler, if I remember correctly, once when they had first got the 604e, then Steve came in and they stopped spending money for Moto to support a compiler for them. From what I see it seems that Apple would like to keep their fate in their own hands. So I'm wondering what the changes could lead to?? This could be really good news for us. I don't think that Apple has had a really good compiler for many years and it looks like they are getting one now. Maybe that is the reason that there are no new developer versions of 10.2 floating around, Apple is keeping the feature set the same and they are just making changes to the compiler and seeing what kind of assembly it spits out. Make change, recompile, distribute the results, review the new code, make sure it works, and see how well optimized the code is. It looks like Apple is making an automatic optimizer like Intel has, or at least along those lines.





Discuss, correct, weigh in...



Ty

applenut

It's fnny, several months ago MOSR posted a similar report. I really hope they are making some strides. Anything could help and from what I have heard the current GCC comiler sucks for performance

low-fi

I think it was Andrew Welch over at the MacNN boards mentioned something along those lines too, IIRC. Performance is always useful, especially when it comes to Mac OS X...



Hopefully we will reap the benefit in the 10.2 release.



AJ

moogs

So, if much of 10.2 may be simply fixing some bugs and recompiling to create much more optomized / responsive code...does that mean Adobe and Microsoft and everyone else will need to recompile their finished apps to take advantage? Will there be a way they could do this via an updater of some kind, or would we have to shell out more $$ to get the update CDs?

airsluf

moogs

True Sluf,



Probably most developers would wait until the next upgrade to recompile their applications vs. recompiling and making the update available for just the cost of the CD and shipping. Althoug I suppose they could just spin it as another dot release that's too big for download. Either way having a mix of initial rev and recompiled apps, running on a mix of initial rev and recompiled OS builds would probably lead to a lot of support headaches. More likely they'll just wait till the next version and *require* the recompiled OS to run.

cowerd

10.2 is supposed to also to finally synch Darwin up with FreeBSD 4.4 [though 4.5 stable is now out]. So I imagine its going to be another large 10.1 style "update."

airsluf

brendon

Quote:



*** Gigahertz UltraSPARC III SPEC Surprise ***

By Kevin Krewell {1/14/02-01}



Sun pulled more than one trick out of its hat with the introduction of the latest speed grade for the UltraSPARC III. For this most recent 1,050MHz version, Sun used the same 0.15-micron, low-k dielectric TI semiconductor process it previously used for the 900MHz US III.



Sun has not put much credence in benchmark results and has not been an exceptional performer on SPEC benchmarks (see MPR 9/4/01-02, "900MHz UltraSPARC III Ready to Ship"). However, the latest US III produced surprising SPEC numbers, with one benchmark in particular showing an amazing increase over previous Sun benchmarks. The base

score of 9,389 for the SPECfp2000 program 179.art is roughly four times the score of its closest competitor, the 800MHz Itanium. The combined SPECfp2000 (base) result of 701 virtually ties the 703 score achieved by the 800MHz Itanium, although it still trails the 1,098 score produced by the 1.3GHz Power 4. Although these new US III results

are partially the result of the higher frequency and an improved translation look-aside buffer (TLB), in large part the improvements are owing to a new Forte Developer 7 compiler. The new benchmark results now put the 1,050MHz UltraSPARC III in the middle of the high-performance pack

instead of at the end of its tail. The US III at 1,050MHz is scheduled to be available for customer shipments in 1Q02. (The full version of this article is available online to Microprocessor Report subscribers at <a href="http://www.mdronline.com/mpr/h/2002/0114/160201.html"; target="_blank">http://www.mdronline.com/mpr/h/2002/0114/160201.html</a>;



End Quote



Just goes to show what a really good compiler can do for performance, here is to hoping that Apple can be as successful at making compiler improvements as Sun. The PowerPC should have good SPEC numbers, gcc 3.1 could be the answer. gcc3.1 and 10.2 could be a potent combination.



Ty

syn

I want to believe!



According to Andrew Welsh of Ambrosia fame, a recompile with gcc 3.0 results in a 10% speed increase... This is good.

moogs

*Mmmm...10 percent iiincreeeeease* *drools*

arakageeta

Let's just hope there aren't any bugs in the new compiler (that can happen from time to time).

stimuli

I seriously doubt Apple uses GCC to compile their code. There are many excellent commercial compilers (CodeWarrior, for one) that are geared specifically for PPC.



GCC is for small time developers and people who want to compile unix code on their OSX box. Apple doesn't want their apps to crawl, so they are optimizing the compiler that everyone else will likely be using.

cowerd

[quote]I seriously doubt Apple uses GCC to compile their code. There are many excellent commercial compilers (CodeWarrior, for one) that are geared specifically for PPC.<hr></blockquote>

From my few failed attempts to build Darwin and Darwin parts, GCC is the only way to build the that layer of the OS. While its not all of OSX, its substantial enough that Apple is commiting serious effort to optimizing it for PPC code.

moogs

Odd. I've heard that CodeWarrior's compiler sucks badly, among other aspects of their IDE. What does PB use to compile apps? There's something in the Dev directory called CpMac...but it's a small file...related perhaps?



I don't see why Apple *wouldn't* use gcc based on what little I know of it.

graphiteman

[quote]Originally posted by Moogs ?:

<strong>Odd. I've heard that CodeWarrior's compiler sucks badly, among other aspects of their IDE. What does PB use to compile apps? There's something in the Dev directory called CpMac...but it's a small file...related perhaps?



I don't see why Apple *wouldn't* use gcc based on what little I know of it.</strong><hr></blockquote>



I believe that CpMac copies files with resource forks. That is something that the cp command cannot do. Someone please correct me if I am wrong.

code master

PB does indeed use gcc. And I believe (especially from Andrew Welch's post) that X is compiled in gcc. It is not a trivial compiler and it is going to get a lot better in v3.1.

airsluf

razzfazz

[quote]Originally posted by AirSluf:

<strong>Recompiling the OS alone shouldn't cause any difficulties with existing applications. They only see the interfaces which would be the same, not the differently compiled executable code.

</strong><hr></blockquote>



Hmm, not sure, couldn't C++ name mangling cause interopability issues when using different compilers?



Bye,

RazzFazz

razzfazz

[quote]Originally posted by stimuli:

<strong>I seriously doubt Apple uses GCC to compile their code. There are many excellent commercial compilers (CodeWarrior, for one) that are geared specifically for PPC.</strong><hr></blockquote>



Does CodeWarrior have working Objective-C support at all?



Bye,

RazzFazz

amorph

[quote]Originally posted by RazzFazz:

<strong>



Does CodeWarrior have working Objective-C support at all?

</strong><hr></blockquote>



Depends on your definition of "working."