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>
This commit updates the ugni btl to make use of multiple device
contexts to improve the multi-threaded RMA performance. This commit
contains the following:
- Cleanup the endpoint structure by removing unnecessary field. The
structure now also contains all the fields originally handled by the
common/ugni endpoint.
- Clean up the fragment allocation code to remove the need to
initialize the my_list member of the fragment structure. This
member is not initialized by the free list initializer function.
- Remove the (now unused) common/ugni component. btl/ugni no longer
need the component. common/ugni was originally split out of
btl/ugni to support bcol/ugni. As that component exists there is no
reason to keep this component.
- Create wrappers for the ugni functionality required by
btl/ugni. This was done to ease supporting multiple device
contexts. The wrappers are thread safe and currently use a spin
lock instead of a mutex. This produces better performance when
using multiple threads spread over multiple cores. In the future
this lock may be replaced by another serialization mechanism. The
wrappers are located in a new file: btl_ugni_device.h.
- Remove unnecessary device locking from serial parts of the ugni
btl. This includes the first add-procs and module finalize.
- Clean up fragment wait list code by moving enqueue into common
function.
- Expose the communication domain flags as an MCA variable. The
defaults have been updated to reflect the recommended setting for
knl and haswell.
- Avoid allocating fragments for communication with already
overloaded peers.
- Allocate RDMA endpoints dyncamically. This is needed to support
spreading RMA operations accross multiple contexts.
- Add support for spreading RMA communication over multiple ugni
device contexts. This should greatly improve the threading
performance when communicating with multiple peers. By default the
number of virtual devices depends on 1) whether
opal_using_threads() is set, 2) how many local processes are in the
job, and 3) how many bits are available in the pid. The last is
used to ensure that each CDM is created with a unique id.
Signed-off-by: Nathan Hjelm <hjelmn@lanl.gov>
This commit adds support for Cray Aries atomic operations. This
includes 32-bit and floating point support.
Signed-off-by: Nathan Hjelm <hjelmn@lanl.gov>
