With Open MPI 5.0, the decision was made to stop building
3rd-party packages, such as Libevent, HWLOC, PMIx, and PRRTE as
MCA components and instead 1) start relying on external libraries
whenever possible and 2) Open MPI builds the 3rd party
libraries (if needed) as independent libraries, rather than
linked into libopen-pal.
This patch moves libevent from an MCA framework to a stand-alone
library built outside of OPAL. A wrapper in opal/util is provided
to minimize the unnecessary changes in the rest of the code. When
using the internal Libevent, it will be installed as a stand-alone
libevent.a, instead of bundled in OPAL. Any pre-installed version
of Libevent at or after 2.0.21 is preferred over the internal
version.
Signed-off-by: Brian Barrett <bbarrett@amazon.com>
There are now four functions and one global constant:
* opal_progress_thread_name: the name of the OPAL-wide async progress
thread. If you have general purpose events that you need to run in
*a* progress thread, but not a *dedicated* progress thread, use this
name in the functions below to glom your events on to the general
OPAL-wide async progress thread.
* opal_progress_thread_init(): return an event base corresponding to a
progress thread of the specified name (a progress thread will be
created for that name if it does not already exist).
* opal_progress_thread_finalize(): decrement the refcount on the
passed progress thread name. If the refcount is 0, stop the thread
and destroy the event base.
* opal_progress_thread_pause(): stop processing events on the event
base corresponding to the progress thread name, but do not destroy
the event base.
* opal_progess_thread_resume(): resume processing events on the event
base corresponding to a previously-paused progress thread name.
