(j3.2006) (SC22WG5.3636) [ukfortran] [Fwd: Preparing for the Tokyo meeting]

Jim Xia jimxia
Thu Nov 6 14:35:14 EST 2008

j3-bounces at j3-fortran.org wrote on 11/06/2008 01:28:36 PM:

> [image removed] 
> (j3.2006) (SC22WG5.3633) [ukfortran] [Fwd: Preparing for the Tokyo 
> Bill Long 
> Vectorization (either SSE or X2)  is not an alternative to coarrays. 
> They coexist and complement each other.  SSE is still vectorization. 
> And I would expect the length of the registers to get longer in the 
> future as chip vendors try to boost performance at fixed clock rates.
> >     b) Because of that, SSE optimisations are handled by all compilers 
> > similar ways to instruction scheduling, and not like true 
vectorisation, as
> > was used on the IBM 3090, Hitachi S-3600, many Fujitsus, almost all 
> > and so on.
> >
> > 
> I can't speak for IBM, Hitachi, or Fujitsu, but at least I know now you 
> are not aware of what happens in Cray's compiler.

You certainly can't speak for IBM :-)  And we can discuss these issues 
during the Tokyo meeting.  BTW I really lost track on the topics discussed 
in this *LONG* thread of "Preparing for the Tokyo meeting".  But two 
points I was surprised to see: 1.) there are people assume compiler will 
only support coarray (i.e. abandon serial Fortran) if coarrays are kept in 
F08.  It's rather a disturbing argument.  2.) I certainly don't see how 
vectorization replaces parallel programming.  Many Fortran programmers may 
have never used a vector machine, but I'll be surprised if they never used 
a multi-processor machine.


Jim Xia

RL Fortran Compiler Test
IBM Toronto Lab at 8200 Warden Ave, Markham, On, L6G 1C7
Phone (905) 413-3444  Tie-line 313-3444
email: jimxia at ca.ibm.com
D2/YF7/8200 /MKM
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