[mpi3-coll] array parameters in nonblocking collectives

[Rajeev Thakur]

That means the MPI implementation would need to make a copy of
potentially large lists. Reference counting won't work here. And the
user could easily issue several nonblocking calls in a row. Ouch.
 
Rajeev
 


  _____  

From: mpi3-coll-bounces at lists.mpi-forum.org
[mailto:mpi3-coll-bounces at lists.mpi-forum.org] On Behalf Of Graham,
Richard L.
Sent: Saturday, August 01, 2009 9:57 AM
To: 'mpi3-coll at lists.mpi-forum.org'
Subject: Re: [mpi3-coll] array parameters in nonblocking collectives



I would expect that the user arguments shouild not be expected to be
preserved in the user's arrays between posting the collectives and
completing them.

Rich



  _____  

From: mpi3-coll-bounces at lists.mpi-forum.org 
To: Torsten Hoefler 
Cc: MPI-3 Collective Subgroup Discussions 
Sent: Sat Aug 01 09:56:50 2009
Subject: [mpi3-coll] array parameters in nonblocking collectives 





Hi, 

I have one question about the array parameters (sendcounts, recvcounts,
sdispls and rdispls) in nonblocking collectives such as MPI_IALLTOALLV.
Are callers allowed to modify/destroy those arrays upon the return of
the calls, or they must wait until after the MPI_WAIT call?  I could not
find the correct behavior defined in the latest proposal
(nbc-proposal-rev-6.2.pdf) and do not remember having discussion on
such. 
I think this issue is quite unique to nonblocking collective
communication calls since arrays in other MPI nonblocking calls are
arrays of MPI objects, for which the correct handling is well defined.
So it needs to be clarified. 
Am I missing something? 

Thanks 
Bin Jia
Communication Protocol Development
Advanced Clustering Technology Team, IBM STG
Poughkeepsie, NY 12601
Tel: 845-433-6301(T/L 293-) 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mpi-forum.org/pipermail/mpiwg-coll/attachments/20090801/c409499d/attachment-0001.html>