2009/6/16 Øyvind Kolås <[email protected]>: > Locking mutexes for such accesses, perhaps even over batches of tiles > when reading/writing a rectangle of pixels I expect to be detrimental > to performance only if the parallellization is implemented so that the > threads will be blocking each others access. This should be avoidable.
In my experience, lock/unlock pairs hurt performance even if threads are not interfering. A lock creates a memory barrier and, even if the processors are not contending, caches must be synchronised and flushed. I imagine the overhead varies a lot with the architecture. Anyway! This is a theoretical concern at the moment I guess. John _______________________________________________ Gegl-developer mailing list [email protected] https://lists.XCF.Berkeley.EDU/mailman/listinfo/gegl-developer
