This commit improves the injection rate and latency for RDMA
operations. This is done by the following improvements:
- If C11's _Thread_local keyword is available then always use the
same virtual device index for the same thread when using RDMA. If
the keyword is not available then attempt to use any device that
isn't already in use. The binding support is enabled by default but
can be disabled via the btl_ugni_bind_devices MCA variable.
- When posting FMA and RDMA operations always attempt to reap
completions after posting the operation. This allows us to
better balance the work of reaping completions across all
application threads.
- Limit the total number of outstanding BTE transactions. This
fixes a performance bug when using many threads.
- Split out RDMA and local SMSG completion queue sizes. The RDMA
queue size is better tuned for performance with RMA-MT.
- Split out put and get FMA limits. The old btl_ugni_fma_limit MCA
variable is deprecated. The new variable names are:
btl_ugni_fma_put_limit and btl_ugni_fma_get_limit.
- Change how post descriptors are handled. They are no longer
allocated seperately from the RDMA endpoints.
- Some cleanup to move error code out of the critical path.
- Disable the FMA sharing flag on the CDM when we detect that there
should be enough FMA descriptors for the number of virtual devices
we plan will create. If the user sets this flag we will not unset
it. This change should improve the small-message RMA performance by
~ 10%.
Signed-off-by: Nathan Hjelm <hjelmn@lanl.gov>
b0ac6276a6