On Wed, Mar 04, 2020 at 05:28:12AM -0800, Matthew Wilcox wrote: > On Wed, Mar 04, 2020 at 06:55:47AM +0000, Al Viro wrote: > > On Tue, Mar 03, 2020 at 11:23:39PM -0600, Eric W. Biederman wrote: > > > Do the xfs-tests cover that sort of thing? > > > The emphasis is stress testing the filesystem not the VFS but there is a > > > lot of overlap between the two. > > > > I do run xfstests. But "runs in KVM without visible slowdowns" != "won't > > cause them on 48-core bare metal". And this area (especially when it > > comes to RCU mode) can be, er, interesting in that respect. > > > > FWIW, I'm putting together some litmus tests for pathwalk semantics - > > one of the things I'd like to discuss at LSF; quite a few codepaths > > are simply not touched by anything in xfstests. > > Might be more appropriate for LTP than xfstests? will-it-scale might be > the right place for performance benchmarks. Might be... I do run LTP as well, but it's still a 4-way KVM on a 6-way amd64 host (phenom II X6 1100T) - not well-suited for catching scalability issues. Litmus tests mentioned above are more about verifying the semantics; I hadn't moved past the "bunch of home-grown scripts creating setups that would exercise the codepaths in question + trivial pieces in C, pretty much limited to syscall()" stage with that; moving those to LTP framework is something I'll need to look into. Might very well make sense; for now I just want a way to get test coverage of that code with minimal headache.
