On Sun, Jul 13, 2014 at 10:25 PM, NeilBrown <neilb@xxxxxxx> wrote: > On Sun, 13 Jul 2014 22:00:12 -0400 Trond Myklebust > <trond.myklebust@xxxxxxxxxxxxxxx> wrote: > >> On Sun, Jul 13, 2014 at 9:28 PM, NeilBrown <neilb@xxxxxxx> wrote: >> > NFS current abort and attempt at filename lookup in RCU mode. >> > This can have serious performance impact on a highly parallel load. >> > >> > The "Makefile" below generates just such a load. On a 40-core >> > machine "make -j 40" is about 6 times as fast at "make -j 5" >> > when a local filesystem is used (e.g. XFS), but as much as half >> > as fast when NFS is used. >> > With this patch set, "make -j 40" is about 3 times as fast as >> > "make -j 5" on NFS, and "perf" data doesn't show spinlocks to be a big >> > problem any more. >> > >> > This is a re-submission with a few small improvements of a patch set >> > posted in March. Since then I have recieved confirmation that it >> > definitely fixes the problem, when combined with a patch set which >> > enhances autofs4 in a similar way. So it has had quite a bit of >> > testing. >> >> Hi Neil, >> >> What kind of tests have you personally (or SuSE if relevant) performed? >> Have you run this under NFSometer in order to check for regressions, >> and if so on what workloads? >> >> The above are not requirements in order to get the patches into >> mainline, I'm just curious. > > I hadn't come across NFSometer before, looks useful! Dros Adamson is the main developer. He'd be happy to take any feedback you may have. > The only testing is that Makefile, and that was done mostly by the customer. > > Further, that testing was a version of the patchset for Linux 3.0. > This particular patchset I've only tested lightly on my little 2-core test > machine. > I'm certainly happy to try beating on it a bit hard, and can see if I can get > access to an 80-core machine that I had a brief play with a while back and do > some more testing there. As I said, it's not required for merging, but would definitely be an interesting test in order to see how it affects NFS performance in general. If you have access to a good test setup with an interesting workload, then I'd love to see the results of a "before vs after" comparison using nfsometer. -- Trond Myklebust Linux NFS client maintainer, PrimaryData trond.myklebust@xxxxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
