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! 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. NeilBrown
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