HI folks, The following 5 patches to xfs_repair improve scalability on high IOPS devices. They remove contention points that limit the number of IO threads that we can use, whilst also protecting against using too much concurrency. The first patch removes a contention point in a 3rd party translation library by avoiding translating static data repeatedly. The second separates the per-ag locks into separate cachelines, so we don't get threads working on different AGs contending on cachelines shared by non-shared locks. THe third parallelises phase 6, which was never done because the original repair parallelism work didn't show it to be a significant contributor to runtime. Even serialised it was as fast as the parallelised phases. However, that's a different story now with SSDs - it's the only phase that is CPU bound because it doesn't spread the work across multiple CPUs, and so is by far the slowest phase of repair on SSDs. The fourht patch corrects a problem with CPU usage in the buffer cache - the hash table distributions are awful. Finally, the last patch fixes a problem reported by Michael Semon where too much concurrency was being used by xfs_repair and hence failing because it was unable to allocate threads. Cheers, Dave. _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
