On Mon, 2010-08-02 at 11:36 -0400, Alberto Canestrelli wrote:
> Thanks,
> ok that is not my problem I never read a data from the posted receive
> before the correspondent WAIT. Now the last question is: what could
> happen if I am reading the data from the posted send? I do it plenty of
> times
I can't give you a complete answer, but I think this is less an MPI
question and more of a Fortran question. The question is if you have a
Fortran derived type, one of whose components is a POINTER, what does
the data structure look like in linear memory? I could imagine the
answer is impleme
Hi Terry:
It is indeed the case that the openib BTL has not been initialized. I
ran with your tcp-disabled MCA option and it aborted in MPI_Init.
The OFED stack is what's included in RHEL4. It appears to be made up of
the RPMs:
openib-1.4-1.el4
opensm-3.2.5-1.el4
libibverbs-1.1.2-1.el4
How can I
For reading the data from an isend buffer to cause problems, the
underlying hardware would need to have very unusual characteristic that
the MPI implementation is exploiting. People have imagined hardware
characteristics that could make reading an Isend buffer a problem but I
have never heard
For OMPI I believe reading the data buffer given to a posted send will
not cause any problems.
Anyone on the list care to disagree?
--td
Alberto Canestrelli wrote:
Thanks,
ok that is not my problem I never read a data from the posted receive
before the correspondent WAIT. Now the last questi
Thanks,
ok that is not my problem I never read a data from the posted receive
before the correspondent WAIT. Now the last question is: what could
happen if I am reading the data from the posted send? I do it plenty of
times! possible consequences?Can you guarantee me that this approach is
saf
In the posted irecv case if you are reading from the posted receive
buffer the problem is you may get one of three values:
1. pre irecv value
2. value received from the irecv in progress
3. possibly garbage if you are unlucky enough to access memory that is
at the same time being updated.
Thanks,
it was late in the night yesterday and i highlighted STORES but I
meanted to highlight LOADS! I know that
stores are not allowed when you are doing non blocking send-recv. But I
was impressed about LOADS case. I always do some loads of the data
between all my ISEND-IRECVs and my WAITs. C
I believe it is definitely a no-no to STORE (write) into a send buffer
while a send is posted. I know there have been debate in the forum to
relax LOADS (reads) from a send buffer. I think OMPI can handle the
latter case (LOADS). On the posted receive side you open yourself up
for some race
My guess is from the message below saying "(openib) BTL failed to
initialize" that the code is probably running over tcp. To absolutely
prove this you can specify to only use the openib, sm and self btls to
eliminate the tcp btl. To do that you add the following to the mpirun
line "-mca btl
Hi,
I have a problem with a fortran code that I have parallelized with MPI.
I state in advance that I read the whole ebook "Mit Press - Mpi - The
Complete Reference, Volume 1" and I took different MPI classes, so I
have a discrete MPI knowledge. I was able to solve by myself all the
errors I b
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