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Subject: Re: [OMPI users] Memchecker report on v1.3b2 (includes potential bug reports)
From: Shiqing Fan (fan_at_[hidden])
Date: 2008-11-19 13:59:57


Hi George,

>>> 4) Well, this sounds reasonable, but according to the MPI-1 standard
>>> (see page 40 for non-blocking send/recv, a more detailed explanation in
>>> page 30):
>>>
>>> "A nonblocking send call indicates that the system may start copying
>>> data out of the send buffer. The sender should */not access*/ any part
>>> of the send buffer after a nonblocking send operation is called, until
>>> the send completes."
>>>
>>> So before calling MPI_Wait to complete an isend operation, any
>>> access to
>>> the send buffer is illegal. It might be a little strict, but we have to
>>> do what the standard says.
>
> This have been changed in the new version of the MPI standard (2.1).
> There is no restriction anymore regarding the read operations on the
> buffers used for non-blocking sends.
Do you mean the next coming version of MPI standard? Because checking
again standard 2.1 , I didn't see any changes of those paragraphs. See
MPI Standard 2.1 (PDF version), page 52, and page 41.

Regards,
Shiqing

>
> We should modify the memchecker accordingly.
>
> george.
>
>
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