POV-Ray : Newsgroups : povray.macintosh : G5 optimization Server Time
25 Oct 2021 22:36:42 EDT (-0400)
  G5 optimization (Message 1 to 3 of 3)  
From: popov
Subject: G5 optimization
Date: 2 Feb 2005 08:50:00
Message: <web.4200d9c11bb956ed95579c20@news.povray.org>
Hi,

I'm trying to built an optimized commandline version of Povray 3.6.1 based
on the latest unix tarball on a 2GHz Powermac G5 running OSX 10.3.7.

In order to optimize for the G5, my gcc compiler flags are -O3 -mcpu=G5
-mtune=G5 -mpowerpc-gpopt -mpowerpc64

Compilation is successful, however running povray -benchmark results in a
segmentation fault at the very beginning of execution.

The reason of the segmentation fault seems to be the -mpowerpc64
optimization flag. If I compile without -mpowerpc64, everything is working
fine and I get a benchmark of 36 minutes.

Is the 3.6.1 source not compatible with the mpowerpc64 flag?

Because this flag is turned on when compiling with -fast (this turns on
various optimization flags), I get also a segmentation fault.

My gcc compiler is:
gcc (GCC) 3.3 20030304 (Apple Computer, Inc. build 1671)

Any idea?


Post a reply to this message

From: Thorsten Froehlich
Subject: Re: G5 optimization
Date: 2 Feb 2005 09:03:24
Message: <4200ddac$1@news.povray.org>
popov wrote:
> In order to optimize for the G5, my gcc compiler flags are -O3 -mcpu=G5
> -mtune=G5 -mpowerpc-gpopt -mpowerpc64
> 
> Compilation is successful, however running povray -benchmark results in a
> segmentation fault at the very beginning of execution.
> 
> The reason of the segmentation fault seems to be the -mpowerpc64
> optimization flag. If I compile without -mpowerpc64, everything is working
> fine and I get a benchmark of 36 minutes.
> 
> Is the 3.6.1 source not compatible with the mpowerpc64 flag?

The flag -mpowerpc64 is simply wrong in this context.  I recommend you read 
and understand the Apple developer documentation or don't build POV-Ray 
yourself.  It is not feasible to explain a topic like this in newsgroup posting.

	Thorsten


Post a reply to this message

From: popov
Subject: Re: G5 optimization
Date: 2 Feb 2005 09:40:00
Message: <web.4200e4c6394e2821d95579c20@news.povray.org>
Thorsten Froehlich <tho### [at] trfde> wrote:
> popov wrote:
> > In order to optimize for the G5, my gcc compiler flags are -O3 -mcpu=G5
> > -mtune=G5 -mpowerpc-gpopt -mpowerpc64
> >
> > Compilation is successful, however running povray -benchmark results in a
> > segmentation fault at the very beginning of execution.
> >
> > The reason of the segmentation fault seems to be the -mpowerpc64
> > optimization flag. If I compile without -mpowerpc64, everything is working
> > fine and I get a benchmark of 36 minutes.
> >
> > Is the 3.6.1 source not compatible with the mpowerpc64 flag?
>
> The flag -mpowerpc64 is simply wrong in this context.  I recommend you read
> and understand the Apple developer documentation or don't build POV-Ray
> yourself.  It is not feasible to explain a topic like this in newsgroup posting.
>
>  Thorsten

Hmm, according to Apple Technical Note TN2086, the mpowerpc64 flag enables
the g5's native 64-bit long long support for greatly enhanced performance
when working with long long. It is common practice to use this flag on the
G5.

If -mpowerpc64 is simply wrong, -fast is also simply wrong because it turns
mpowerpc64 on.


Post a reply to this message

Copyright 2003-2021 Persistence of Vision Raytracer Pty. Ltd.