blocking probe

[dimitrijejankov]

Hi so I want to use ucx to replace MPI in my research project. One problem I have encountered is that you only have a non-blocking probe "ucp_tag_probe_nb". What would be the best way to replace calls to "MPI_Mprobe"?

[brminich]

Hi,
You can replace MPI_Mprobe by ucp_tag_probe_nb() with remove flag set to 1, i. e.
ucp_tag_probe_nb(worker, tag, tag_mask, 1, info);
This routine returns msg handle which can further be passed to ucp_tag_msg_recv_nb to receive the message.
Also to make it blocking you can use a loop, like it is done in OMPI here:
https://github.com/open-mpi/ompi/blob/master/ompi/mca/pml/ucx/pml_ucx.c#L1029

[dimitrijejankov]

Thanks a lot :)