[Omp] Directive 'sharable' or inclusion of Cluster OpenMP?

[Shah, Sanjiv]

Hello Tobias,

I work at Intel and am one of the proponents of this.  

Speaking as an OpenMP representative, this technology
needs to be validated as valuable before it can be 
included in the standard specifications.

This is similar to other proposals e.g., the taskq
proposal that KAI (Intel) introduced in 1999 and is
now under consideration for standardization.
If this is valuable, we hope to be able to do it in
a shorter time frame than the 7 years it has take 
for taskq, but that's the general idea.

Speaking as an Intel representative, I love your
message and hope we can work together to make
this technology successful and included in the
standard.  Please feel free to send me private
email if you'd like to pursue this further.

Thanks,
Sanjiv



--
Sanjiv, 217-403-4244

-----Original Message-----
From: omp-bounces at openmp.org [mailto:omp-bounces at openmp.org] On Behalf
Of Tobias Burnus
Sent: Wednesday, May 10, 2006 7:08 PM
To: omp at openmp.org
Subject: [Omp] Directive 'sharable' or inclusion of Cluster OpenMP?

Hello,

Intel's new compiler supports something they call "Cluster OpenMP". This
allows to run OpenMP programs on distributed-memory systems.

When implementing OpenMP for distributed-memory systems, one encounters
the problem (if I understood it correctly) that in OpenMP almost
everything is shared between threads, except for local variables whereas
for programs running on distributed memory almost all variables are
local - except those that are synchronized. Intel introduced a new
directive 'shareable', which denotes variables that are
shared/synchronized by the "Distributed Shared-Memory manager". Some
variables are, however, automatically marked as shareable.
(Actually, 'shareable' is not the only new item; the _CLUSTER_OPENMP
macro and kmp_shareable_malloc etc. also exists.)

I do like it a lot that I can now run (in principle) my OpenMP program
instead of on 2 cores (or 4 cores) on 2*124 cores, but I'd like to see
this enhancement to be standardized so I have the chance that an other
compiler vendor will follow suit.
The OpenMP standard seems to be the right place for that :-)

Intel's Whitepaper can be found at
  
http://www.intel.com/cd/software/products/asmo-na/eng/compilers/285865.h
tm

Intel's user manual at
 
http://softwareforums.intel.com/attachments/ids/11/3796/1/UsersGuide.pdf

Tobias
_______________________________________________
Omp mailing list
Omp at openmp.org
http://openmp.org/mailman/listinfo/omp