[Beowulf] Table of best compiler flags for different CPUs?

[Joe Landman]

Hi Steve:

Try -fastsse with the Portland group compilers.   You might also try 
-Mipa=fast .   For laughs, pull down PathScale as well.  When it is 
faster, it is usually by a bit.  When it isn't, they are pretty close.

Joe

Steve Cousins wrote:
> 
> On Tue, 10 May 2005, Kozin, I (Igor) wrote:
> 
>>It is generally a good idea to look up what other
>>published benchmarks used to build their codes.
>>Two obvious good sources are SPEC and Stream.
>>http://www.polyhedron.com/ is quite useful too.
>>But I must admit that the obscure options used
>>there were seldom useful to me apart from building
>>the respective codes on respective hw.
> 
> 
> Thanks.  Someone else suggested spec.org to me offline.  This does have
> valuable information but I was hoping that someone had already created a
> table like this and it would save time if they might share it.
> 
> 
>>>>I am interested in what combinations of compilers and 
>>>>switches will give a better comparison, as well as run our 
>>>>code faster. 
>>
>>serial or parallel? Please, post a link if published.
> 
> 
> I haven't really posted but here is what I have found:
> 
> CPU:         	Speed   CPUs	Time to run:	Compiler and Flags
> =============	=======	====	============	====================
> PIII 		866 Mhz	  2 	30:10		pgf77 -fast -Mconcur	
> Athlon 2800+	2.1 Ghz   1	13:26		pgf77 -fast -Mconcur
> SGI MIPS 	400 Mhz	  4	12:08		f77 -apo -O2 
> Athlon 3000+	2.1 Ghz   1	11:27		pgf77 -fast -Mconcur
> Athlon 2800+	2.1 Ghz   1	10:19		pgf77 -fast -Mconcur
> Desktop G5 	2.0 Ghz	  1	9:15		xlf_r  *  
> Xeon 		3.0 Ghz   1	9:08		pgf77 -fast -Mconcur
> Desktop G5 	2.0 Ghz	  2	7:20		xlf_r  *  
> Opteron 	1.6 Ghz	  1	7:15		pgf77 -fast -Mconcur
> Xserve G5 	2.0 Ghz	  2	7:11		xlf_r  *  
> SGI MIPS 	400 Mhz	  8 	6:55		f77 -apo -O2 
> Opteron 	2.2 Ghz	  1	6:10		pgf77 -fast -Mconcur
> Opteron		1.6 Ghz	  2	5:37		pgf77 -fast -Mconcur
> Opteron 	2.6 Ghz	  1	5:32		pgf77 -fast -Mconcur
> Xeon 		3.0 Ghz   1	5:29		pgf77 -fast -Mconcur
> Opteron 	2.6 Ghz	  1	3:12		pgf77 -fast -Mconcur
> 
> * flags for xlf_r:  -O5 -qstrict -qarch=g5 -qtune=g5 -qsmp -qunroll=yes
> 
> The program that was run is a stripped down ocean model (Princeton Ocean
> Model) that reads in initial conditions at the beginning and then does a
> one day run without any further I/O.
> 
> Cheers,
> 
> Steve
> 
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-- 
Joseph Landman, Ph.D
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Scalable Informatics LLC,
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