[mpich-discuss] How to use non-blocking send/receive without calling MPI_Wait

Lei Shi lshi at ku.edu
Thu Apr 2 23:44:04 CDT 2015


Hi Junchao,

Thanks for your reply. For my case, I don't want to check the data have
been received or not. So I don't want to call MPI_Test or any function to
verify it. But my problem is like if I ignore calling the MPI_Wait, just
call Isend/Irev, my program freezes for several sec and then continues to
run. My guess is probably I messed up the MPI library internal buffer by
doing this.

On Thu, Apr 2, 2015 at 7:25 PM, Junchao Zhang <jczhang at mcs.anl.gov> wrote:

> Does MPI_Test fit your needs?
>
> --Junchao Zhang
>
> On Thu, Apr 2, 2015 at 7:16 PM, Lei Shi <lshi at ku.edu> wrote:
>
>> I want to use non-blocking send/rev MPI_Isend/MPI_Irev to do
>> communication. But in my case, I don't really care what kind of data I get
>> or it is ready to use or not. So I don't want to waste my time to do any
>> synchronization  by calling MPI_Wait or etc API.
>>
>> But when I avoid calling MPI_Wait, my program is freezed several secs
>> after running some iterations (after multiple MPI_Isend/Irev callings),
>> then continues. It takes even more time than the case with MPI_Wait.  So my
>> question is how to do a "true" non-blocking communication without waiting
>> for the data ready or not. Thanks.
>>
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