GCC compiler optimization flags (Advanced)

kmooney · June 1, 2012, 12:07

Howdy Foamers,

I was wondering if anyone has had any experience in other GCC compiler optimization flags other than the typical -O3. I'm considering a recompile with some architecture specific flags. One option I'm planning on using is '-march=native'. This is supposed to look at your CPU and identify any special vector processors onboard such as SSE or AVX units. I don't believe that you would be able to share binaries with people/machines using different chips however since it becomes more specific than the usual x86 instruction set.

Really just wondering if anyone is familiar with this stuff or has perhaps tried it out. I did a quick timing on an icoFoam run with -O3. I'll let you guys know if I see any speed up from the advanced optimization.

Cheers!

wyldckat · June 1, 2012, 14:33

Greetings Kyle,

Start reading here: http://www.cfd-online.com/Forums/ope...tml#post356486 post #8

By the way, Intel has similar optimization flag lists for each processor of their own.

Best regards,
Bruno

kmooney · June 4, 2012, 13:06

Thanks for the link!

June 1, 2012, 12:07	GCC compiler optimization flags (Advanced)	#1
kmooney Senior Member Kyle Mooney Join Date: Jul 2009 Location: San Francisco, CA USA Posts: 323 Rep Power: 18	Howdy Foamers, I was wondering if anyone has had any experience in other GCC compiler optimization flags other than the typical -O3. I'm considering a recompile with some architecture specific flags. One option I'm planning on using is '-march=native'. This is supposed to look at your CPU and identify any special vector processors onboard such as SSE or AVX units. I don't believe that you would be able to share binaries with people/machines using different chips however since it becomes more specific than the usual x86 instruction set. Really just wondering if anyone is familiar with this stuff or has perhaps tried it out. I did a quick timing on an icoFoam run with -O3. I'll let you guys know if I see any speed up from the advanced optimization. Cheers!

June 1, 2012, 14:33		#2
wyldckat Retired Super Moderator Bruno Santos Join Date: Mar 2009 Location: Lisbon, Portugal Posts: 10,982 Blog Entries: 45 Rep Power: 128	Greetings Kyle, Start reading here: http://www.cfd-online.com/Forums/ope...tml#post356486 post #8 By the way, Intel has similar optimization flag lists for each processor of their own. Best regards, Bruno __________________ OpenFOAM: FAQ \| Getting started Forum: How to get help, to post code/output and forum guide Read this before sending me PM

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June 4, 2012, 13:06		#3
kmooney Senior Member Kyle Mooney Join Date: Jul 2009 Location: San Francisco, CA USA Posts: 323 Rep Power: 18	Thanks for the link!