Compile switches on Macs

Hi!

I found that my opt-settings for gcc give about 10% additional performance (tested with the "bench2" set of files) on my rather old G4. As most folks using their Mac for rendering don't use G3 or older for that, I think it might be a good idea to have an option in the makeall script to compile on recent Macs. What do you think? Maybe even one G4 and one G5 option? Should this be included in the distribution?

My opt-line (based on the proposed PPC-optimizations from gcc 3.3 docs):
set opt="-O2 -DSPEED=200 -mcpu=7400 -mtune=7400 -malign-natural -funroll-loops -fstrict-aliasing -fsched-interblock -falign-loops=16 -falign-jumps=16 -falign-functions=16 -falign-jumps-max-skip=15 -falign-loops-max-skip=15 -ffast-math -mpowerpc-gpopt -fstrict-aliasing"

CU Lars.

Hi!

I found that my opt-settings for gcc give about 10% additional
performance (tested with the "bench2" set of files) on my rather old
G4. As most folks using their Mac for rendering don't use G3 or older
for that, I think it might be a good idea to have an option in the
makeall script to compile on recent Macs. What do you think? Maybe even
one G4 and one G5 option? Should this be included in the distribution?

I think it'd great to include makeall options for the various Gx
processors. Just make sure you still include the G3, since the Father of
Radiance still runs Radiance on a G3 (when he's using his laptop)! The
10% boost on my G4 will be appreciated.

- Rob Guglielmetti
www.rumblestrip.org

I've popped this hint into the wiki: www.radiance-wiki.org

Lars O. Grobe wrote:

···

Hi!

I found that my opt-settings for gcc give about 10% additional performance (tested with the "bench2" set of files) on my rather old G4. As most folks using their Mac for rendering don't use G3 or older for that, I think it might be a good idea to have an option in the makeall script to compile on recent Macs. What do you think? Maybe even one G4 and one G5 option? Should this be included in the distribution?

My opt-line (based on the proposed PPC-optimizations from gcc 3.3 docs):
set opt="-O2 -DSPEED=200 -mcpu=7400 -mtune=7400 -malign-natural -funroll-loops -fstrict-aliasing -fsched-interblock -falign-loops=16 -falign-jumps=16 -falign-functions=16 -falign-jumps-max-skip=15 -falign-loops-max-skip=15 -ffast-math -mpowerpc-gpopt -fstrict-aliasing"

CU Lars.

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I think it'd great to include makeall options for the various Gx
processors. Just make sure you still include the G3, since the Father of
Radiance still runs Radiance on a G3 (when he's using his laptop)!

Just imagine... the master himself posting "rpict doesn't work on my Mac"... and I'd know the answer... :wink:

No, the idea was not to replace the Mac OS X option, but to add an optimized for the folks with the brand new toys.

CU Lars.

Just an FYI, I do use a G3 laptop as Rob points out. However, I also own a dual G5 desktop, so I'm not completely behind the times (although it's only a dual 1.8 GHz, rather than the latest 2.5 model).

Lars, I'm glad you were able to find a combination of gcc options that actually improves rendering speed without causing the code to hang, which is the problem I ran into with the -fast option. This option is supposed to turn on all the local optimizations for the target processor, but it seems to be a bit buggy in the version of gcc installed on my machine, anyway (3.3 20030304, build 1671). In general, I've learned the hard way to distrust the gcc optimizer, so I'm still running with -O2 in my rmake script.

If anyone has trouble with odd results using the faster compile, I suggest they first try recompiling before they tear their hair out trying to find the bug.

-Greg

···

From: Lars O. Grobe <[email protected]>
Date: January 20, 2005 2:12:41 AM PST

I think it'd great to include makeall options for the various Gx
processors. Just make sure you still include the G3, since the Father of
Radiance still runs Radiance on a G3 (when he's using his laptop)!

Just imagine... the master himself posting "rpict doesn't work on my Mac"... and I'd know the answer... :wink:

No, the idea was not to replace the Mac OS X option, but to add an optimized for the folks with the brand new toys.

CU Lars.