[Pharo-project] [Vm-dev] Re: newDelta >0 failed in sqUnixMemory

John M McIntosh johnmci at smalltalkconsulting.com
Fri Jan 30 15:09:04 EST 2009


mmm, let me clarify.  I currently use Apple's GCC 4.0.1 <i686-apple- 
darwin9-gcc-4.0.1>
that works fine for macintel,  3.3 is required for decent performance  
on powerpc.

The version that I worked with Michael on was the LLVM GCC 4.2 and or  
GCC 4.2.  Michael I believe tried GCC 4.3
Michael said:
"after managing to build the VM with the recommended setup I tried  
with newer GCCs (3.45 and 4.3), both significantly slower.
GCC 3.45 about 50%, GCC 4.3 about 80% of GCC 2.95."

With 4.0.1 the compiler optimizations tweaks in the macintosh carbon  
VM build give it a good 10%? better than the defaults optimizations.
However that presupposes  -mtune=prescott -march=pentium-m   which one  
can get away with on the macintosh platform, versus the
bazillion cpu choices & clones on the Wintel side.


On 30-Jan-09, at 9:37 AM, Andreas Raab wrote:

> John M McIntosh wrote:
>> Yes, I can't recall it was what 50% of the performance of a 3.x  
>> compile out of the box, and after *much*
>> tweaking of compiler flags it was mmm just 20% slower..   Well  
>> certainly the performance impact was measured in 10 of percent.
>
> So what do you use today? gcc 4? And how does it stack up  
> performance-wise against a Windows VM on the same box? I personally  
> wouldn't mind moving forward but the results in the past were so  
> godawful that I haven't tried in a long time.
>
> Cheers,
>  - Andreas
>
>> On 30-Jan-09, at 4:33 AM, Michael Rueger wrote:
>>>
>>> John McIntosh and I actually spent some time a few ago compiling  
>>> VMs on
>>> Windows and MacOS with the newest GCCs and ran into a bunch of  
>>> problems,
>>> especially concerning performance. I had to put the work on the back
>>> burner for now, but switching to newer compilers will take a bit of
>>> extra work at some point.
>>>
>>> Michael
>> -- 
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>> John M. McIntosh <johnmci at smalltalkconsulting.com>
>> Corporate Smalltalk Consulting Ltd.  http://www.smalltalkconsulting.com
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>> =====================================================================

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John M. McIntosh <johnmci at smalltalkconsulting.com>
Corporate Smalltalk Consulting Ltd.  http://www.smalltalkconsulting.com
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