[MITgcm-devel] [MITgcm-cvs] MITgcm/tools/build_options CVS Commit

[Menemenlis, Dimitris (3248)]

David and other Pleaides users, as checked in the Pleiades option file only works on 1216 out of 7104 Pleiades nodes.
In a first step, I suggest that we check in 2 separate option files:
(i) a generic option file with SSE4.1 that supports all processors, i.e., including the 5888 Harpertown nodes, and
(ii) a _nehalem option file with SSE4.2 that is specific to the newer 1216 Nehalem processors.
A third option file can be added, if needed, when the Westmere processors become available.
In a second step, if someone has the time to run some proper timing tests, we could implement Constantino's suggestions:

> My suggestions:
> a) Separate optfiles (per queue). It explodes the number of optfiles but solves 
> the problem for good.
> b) The "generic" Pleides optfile uses the -ax instead of the -x flag. That flag 
> builds a generic binary with optional code paths depending on the actual 
> processor used. So I would have a -axSSSE3,SSE4.1 (and in the future ,SSE4.2)
> 
> See the way they do it at
> http://astromatic.iap.fr/wsvn/public/filedetails.php?repname=public+software.swarp&path=%2Ftrunk%2Facx_prog_cc_optim.m4&
> The -ax flag is not as fast as the -x flag as it involves runtime processor ID 
> checks but it will allow the same binary to run everywhere on pleiades.

Let me know if this is acceptable.  Dimitris