On Tue, Jul 19, 2011 at 01:30:22PM -0400, Chris Mason wrote: > We've seen a number of benchmarks dominated by contention on the root > node lock. This changes our locks into a simple reader/writer lock. > They are based on mutexes so that we still take advantage of the mutex > adaptive spins for write locks (rwsemaphores were much slower). Interesting. Do you have set up some artifical benchmarks for this? I wonder if the lack of adaptive spinning has something to do with the slightly slower XFS performance on Joern's flash testing, given that we extensively use the rw_semaphore as the primary I/O mutex, while all others rely on plain mutexes as the primary synchronization primitive. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
