MCS locks and qspinlocks
Posted Mar 12, 2014 23:04 UTC (Wed) by james (subscriber, #1325)
What I'm not sure about is how often this situation will arise in practice. Obviously, you have to have a lock with at least two CPUs waiting for the situation to arise, and an interrupt being handled on the wrong CPU at just the wrong time. It looks like this is sufficiently infrequent that the performance hit when this happens is dwarfed by the performance benefits of the technique, but it would probably be a good idea to retry the benchmark on a machine subject to a network storm.
Posted Mar 13, 2014 3:15 UTC (Thu) by martinfick (subscriber, #4455)
I wonder about that since these locks are meant for highly contentious locks!
Posted Mar 13, 2014 14:30 UTC (Thu) by raven667 (subscriber, #5198)
Posted Mar 13, 2014 11:23 UTC (Thu) by dvrabel (subscriber, #9500)
Posted Mar 13, 2014 15:55 UTC (Thu) by andresfreund (subscriber, #69562)
Preemtion is disabled appropriately during spinlock acquiration IIRC.
Posted Mar 13, 2014 9:58 UTC (Thu) by dgm (subscriber, #49227)
Copyright © 2018, Eklektix, Inc.
Comments and public postings are copyrighted by their creators.
Linux is a registered trademark of Linus Torvalds