Historically these two lists were different due to ompi_free_list_t
dependencies in ompi (mpool). Those dependencies have since been moved
to opal so it is safe to (finally) combine them. The combined free
list comes in three flavors:
- Single-threaded. Only to be used when it is guaranteed that no
concurrent access will be made to the free list. Single-threaded
functions are suffixed with _st.
- Mutli-threaded. To be used when the free list may be accessed by
multiple threads despite the setting of opal_using_threads.
Multi-threaded functins are suffixed with _mt.
- Conditionally multi-threaded. Common use case. These functions are
thread-safe if opal_using_threads is set to true.
Compatibility functions for the ompi_free_list_t and the old accessor
functions (OPAL_FREE_LIST_*) are available while the code base is
transitioned to the new class/functions.
Signed-off-by: Nathan Hjelm <hjelmn@lanl.gov>
- Rename opal_atomic_lifo_t to opal_lifo_t to reflect both atomic and
non-atomic usage. Added new routines (opal_lifo_*_st) for non-atomic
usage as well as routines conditioned off opal_using_threads(). The
atomic versions are always thread safe and the non-atomic are always
not thread safe.
- Add a new atomic lifo implementation that makes use of 128-bit
compare-and-swap. The new implementation should scale better with
larger numbers of threads.
- Add threading unit test for opal_lifo_t.
WHAT: Open our low-level communication infrastructure by moving all necessary components (btl/rcache/allocator/mpool) down in OPAL
All the components required for inter-process communications are currently deeply integrated in the OMPI layer. Several groups/institutions have express interest in having a more generic communication infrastructure, without all the OMPI layer dependencies. This communication layer should be made available at a different software level, available to all layers in the Open MPI software stack. As an example, our ORTE layer could replace the current OOB and instead use the BTL directly, gaining access to more reactive network interfaces than TCP. Similarly, external software libraries could take advantage of our highly optimized AM (active message) communication layer for their own purpose. UTK with support from Sandia, developped a version of Open MPI where the entire communication infrastucture has been moved down to OPAL (btl/rcache/allocator/mpool). Most of the moved components have been updated to match the new schema, with few exceptions (mainly BTLs where I have no way of compiling/testing them). Thus, the completion of this RFC is tied to being able to completing this move for all BTLs. For this we need help from the rest of the Open MPI community, especially those supporting some of the BTLs. A non-exhaustive list of BTLs that qualify here is: mx, portals4, scif, udapl, ugni, usnic.
This commit was SVN r32317.
- move mpool and allocator frameworks back to ompi (from opal)
- specialize the ompi_free_list class to use an mpool instance
- un-specialize opal_free_list to *not* use mpool; just use malloc/free
This commit was SVN r6292.
