I added an extra argument to the CK_COHORT_INIT macro to allow users to specify custom pass limits
when using it. I also added a reference to the paper on which the cohort implementation was based.
The constants and macros in ck_cohort.h didn't conform to CK naming conventions. Additionally, I was able to remove a lot of unnecessary atomic operations and memory fences, which reduced latency by 10-20% and increased throughput using ticket locks by nearly an order of magnitude.
John Wittrock has contributed a phase-fair reader-writer
lock implementation. These locks allow phase fairness
guarantees between readers and writers. This work includes
additional changes and clean-up.
Follow-up work is expected.
Thanks to John Wittrock for patches and Professor Gabriel
Parmer (http://www.seas.gwu.edu/~gparmer/) for advising.
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.
This primarily involved changing the configure script and adding
several utility functions to regressions/common.h for unit testing.
Signed-off-by: Samy Al Bahra <sbahra@appnexus.com>
The distinction between additive/exponential implementation
and geometric implementation does little but confuse users.
The terminology used in ck_backoff now reflects terminology
used in literature.
ck_backoff_gb has been removed.
Execution history exists such that first thread will dequeue
from an uninitialized ring buffer. The unit test has been
(un)fortunate in that it would busy-wait during dequeue.
Full barrier semantics will enforce visibility.
Reported by: Maxime Henrion <mhenrion@gma....>.
Samy Al Bahra
Brendon Scheinman
Samy Al Bahra
David Joseph