speed with 8-processor Mac Pro

[karose]

I just purchased a new Mac Pro and tried the Intel fortran and Absoft fortran compilers on the same exact code.  The speed in running the code with Absoft is much slower and when I look it seems to use 1 processor 99% of the time. The intel compiler makes more use of the 8 processors.

Perhaps I am not using the correct (optimal) flags on the Absoft.  I read to use -apo; are there others I should use as well?  Maybe -O3?

Any suggestions would be appreciated.

Kenny

[Jeremy]

With Absoft Pro Fortran v10.1 for Linux 32/64, Windows and Intel Macs, "-apo" is our only built-in auto parallelizer.  However, "-apo" only applies to loops.  If your program does not have many loops or if the loops can not be parallelized then "-apo" will not do as much for that program.  "-apo" will use as many cores as the computer has in to offer.  If "-apo" does not do as much as you want, then you should take a look at VAST.  VAST is a preprocessor that attempts to parallelize your whole program.

http://www.absoft.com/Absoft_VAST.htm

"-O4" is an optimization.  Same goes for "-speed_math=9" or "-speed_math=10".  Both, "-O4" and "-speed_math=x" (9 or 10 being faster is dependent on the program), options should always be used for your final program.

[karose]

Jeremy

Thanks for the reply.  I will purchase VAST.  But a quick look showed VAST-F Vector and VAST-F Parallel.

Do I purchase the Parallel only or both?  I can see how to us the parallel - pf95.  But can I use both somehow?

I have a brand new Mac Pro.

Thanks

Kenny

[Jeremy]

Crescent Bay Software's VAST-F Vector is currently only supported on Power Processors.

For Absoft Pro Fortran v10/v10.1 on Intel Macs all you will need VAST-F Parallel.