This commit adds a new btl for one-sided and two-sided. This btl
uses the uct layer in OpenUCX. This btl makes use of multiple uct
contexts and per-thread device pinning to provide good performance
when using threads and osc/rdma. This btl has been tested extensively
with osc/rdma and passes all MTT tests on aries and IB hardware.
For now this new component disables itself but can be enabled by
setting the btl_ucx_transports MCA variable with a comma-delimited
list of supported memory domains/transport layers. For example:
--mca btl_uct_memory_domains ib/mlx5_0. The specific transports used
can be selected using --mca btl_uct_transports. The default is to use
any available transport.
Signed-off-by: Nathan Hjelm <hjelmn@lanl.gov>
