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* [Bug other/27541] Support Cluster OpenMP (distributed-memory OpenMP)
[not found] <bug-27541-4@http.gcc.gnu.org/bugzilla/>
@ 2012-02-22 13:57 ` xiaoyuanbo at yeah dot net
0 siblings, 0 replies; 3+ messages in thread
From: xiaoyuanbo at yeah dot net @ 2012-02-22 13:57 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27541
xiaoyuanbo <xiaoyuanbo at yeah dot net> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |xiaoyuanbo at yeah dot net
--- Comment #3 from xiaoyuanbo <xiaoyuanbo at yeah dot net> 2012-02-22 13:02:32 UTC ---
from sql selector
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug other/27541] Support Cluster OpenMP (distributed-memory OpenMP)
2006-05-10 21:57 [Bug other/27541] New: " tobias dot burnus at physik dot fu-berlin dot de
2006-05-10 22:09 ` [Bug other/27541] " pinskia at gcc dot gnu dot org
@ 2006-05-10 22:46 ` tobias dot burnus at physik dot fu-berlin dot de
1 sibling, 0 replies; 3+ messages in thread
From: tobias dot burnus at physik dot fu-berlin dot de @ 2006-05-10 22:46 UTC (permalink / raw)
To: gcc-bugs
------- Comment #2 from tobias dot burnus at physik dot fu-berlin dot de 2006-05-10 22:46 -------
> Is there really a standard for this or just an extension of OpenMP?
I'm not sure whether I understand the question.
Directive wise it is OpenMP augmented by a single directive: "shareable".
This seems to be a single-vendor extension by Intel.
I think they simply took the OpenMP standard and looked how to implement it for
distributed memory.
The problem in inplementing is, as far as I understood, that plainly speaking
OpenMP assumes everything is global whereas distributed programs want to
minimize 'global' (better: shared) variables as they have to be synchronized
and are thus expensive.
Intel added "sharable" to denote explictly such a variable; however, some
variables are automatically marked as shareable.
Thus: Syntaxwise it is a rather small change quickly to be implemented in GOMP.
But the library system behind is a bigger task:
- wrapper main() which initializes helper library, finds settings and starts
the program on m computers (incl. forking of n threads) via rsh/ssh.
- provides synchronization (barrier, data exchange, collection of data etc.)
via
TCP or DAPL, especially for global variables
> Though this is useful a little bit for the Cell where you don't
> really have a distrubuted machine but the memory will be distributed though.
Well, I'm primarily interested to run a number-crunching program
(exciting.sf.net) on more nodes. As it is only parallized using OpenMP (and not
e.g. via MPI), I'm currently limited to 2 CPUs (or one dualcore) on our
cluster. Using Cluster OpenMP with infiniband I could use 2*120 CPUs.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27541
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug other/27541] Support Cluster OpenMP (distributed-memory OpenMP)
2006-05-10 21:57 [Bug other/27541] New: " tobias dot burnus at physik dot fu-berlin dot de
@ 2006-05-10 22:09 ` pinskia at gcc dot gnu dot org
2006-05-10 22:46 ` tobias dot burnus at physik dot fu-berlin dot de
1 sibling, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2006-05-10 22:09 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from pinskia at gcc dot gnu dot org 2006-05-10 22:09 -------
Is there really a standard for this or just an extension of OpenMP?
Though this is useful a little bit for the Cell where you don't really have a
distrubuted machine but the memory will be distributed though.
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever Confirmed|0 |1
Last reconfirmed|0000-00-00 00:00:00 |2006-05-10 22:09:40
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27541
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2012-02-22 13:56 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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[not found] <bug-27541-4@http.gcc.gnu.org/bugzilla/>
2012-02-22 13:57 ` [Bug other/27541] Support Cluster OpenMP (distributed-memory OpenMP) xiaoyuanbo at yeah dot net
2006-05-10 21:57 [Bug other/27541] New: " tobias dot burnus at physik dot fu-berlin dot de
2006-05-10 22:09 ` [Bug other/27541] " pinskia at gcc dot gnu dot org
2006-05-10 22:46 ` tobias dot burnus at physik dot fu-berlin dot de
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