As of MPI 2.2 there is no longer a restriction against read access to a
live send buffer. The wording was changed to now prohibit the user to
"modify". You can look the subsection of Communication Modes in chapter 3
but you will need to compare MPI 2.1 and 2.2 carefully to see the change.
The
At: Richard Treumann . You said "The Forum has decided the send buffer
rule is to restrictive. " Do you mean that you are planning to change
the rule?
At: Terry Frankcombe. If they are going to change the rule everything
will be fine. Do you know why I don't you want to be standard-compliant?
S
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
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
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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