[mpich-discuss] Order of completion in MPI_Waitany

[Thomas Ropars]

Hi Matthieu,

MPI does not provide any guarantee on the completion order of the 
reception requests in this case. More generally, regarding waitAny, the 
MPI-3.0 specification says that "If more than one operation is enabled 
and can terminate, one is arbitrarily
chosen".

Thomas

On 09/19/2013 04:31 PM, Matthieu Dorier wrote:
> Hi,
>
> I would like a precision on the semantics of MPI_Waitany in this 
> situation:
>
> - Process 1 does 2 MPI_Irecv with different tags A and B (the order 
> doesn't matter); it then waits on the two requests with MPI_Waitany.
> - In the mean time, process 2 does an MPI_Send with tag A, then 
> MPI_Send with tag B.
> Can I ensure that MPI_Waitany will always give me the index of the 
> message corresponding to the first MPI_Send, i.e. the one with the tag 
> A, even in situations where process 1 called MPI_Irecv on a tag B first?
>
> Thanks
>
> Matthieu Dorier
> PhD student at ENS Cachan Brittany and IRISA
> http://people.irisa.fr/Matthieu.Dorier
>
>
> _______________________________________________
> discuss mailing list     discuss at mpich.org
> To manage subscription options or unsubscribe:
> https://lists.mpich.org/mailman/listinfo/discuss

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mpich.org/pipermail/discuss/attachments/20130920/fcb09f2b/attachment.html>