This includes fixing acquire semantics on mcs_lock fast path.
This represents an additional fence on the fast path for
acquire semantics post-acquisition.
Upon popular request, added a variant of the ticket spinlock
with trylock support. This is pending additional verification
on other architectures besides x86*. It is still unclear whether
this implementation will be the default as it is has slower
fast path.
Add trylock support to the ck_spinlock validation tests.
It currently only tests ck_spinlock_ticket_t trylock
functionality if available.
Some people might be confused as far as lack of
fencing in the lock. Add a comment to clarify that
old values should not be equal to new values
of current position (where acquiring the current position
already has a global ordering).
Several users in the past have noted it was difficult for them
to decide what spinlock implementation to use. In light of this,
a light-weight greedy default is chosen (currently ck_spinlock_fas).
CK_CC_PACKED will drop structures to one-byte alignment in certain
cases. Obviously, this will mean bad performance on most architectures.
Thanks to Matt Johnson from https://rigel.crhc.illinois.edu/ for
reporting this problem.
Samy Al Bahra
Samy Al Bahra
Samy Al Bahra