osc/ucx: implement rput and rget using ucp_worker_flush_nb [v5.0.x] #10554
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Fallback to the old method of acquiring a request from an atomic operation is preserved. Some networks might provide better performance if the request-based operations do not rely on atomic operations. Some minor fixes to opal_common_ucx_winfo_flush included in this commit. Signed-off-by: Joseph Schuchart <schuchart@icl.utk.edu> (cherry picked from commit eee891f)
janjust
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Jul 11, 2022
janjust
changed the title
This was referenced Aug 9, 2022
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Based on a reply by @yosefe in #9580 (comment) it appears that the way osc/ucx implements request based put and get operations might not work well on older networks. This is an attempt at using ucp_worker_flush_nb instead to acquire a request that completes once the put or get operations have completed without explicitly posting an atomic operation. I don't know the implementation details of ucp_worker_flush_nb but it seems like a cleaner solution to me.
Fallback to the old method of acquiring a request from an atomic operation is preserved in case ucp_worker_flush_nb is not available.
Some minor fixes to opal_common_ucx_winfo_flush are also included in this PR.
@janjust @yosefe is this the correct use of ucp_worker_flush_nb?
@jotabf fyi this might solve the performance issue you're seeing with MPI_Rget. I haven't been able to test it on a network like yours though.
Signed-off-by: Joseph Schuchart schuchart@icl.utk.edu
(cherry picked from commit eee891f)