On Tue, Jul 1, 2014 at 10:10 AM, Jeff Layton <jlayton@xxxxxxxxxxxxxxx> wrote: > > Quite right. I changed the program to be run as root and had each child > process do an setfsuid/setfsgid to a different UID/GID combo: > > [jlayton@tlielax lockperf]$ time sudo ./opentest -n 128 -l 100 /mnt/rawhide/opentest > > real 0m3.448s > user 0m0.078s > sys 0m0.377s > [jlayton@tlielax lockperf]$ time sudo ./opentest -n 128 -l 100 /mnt/rawhide/opentest > > real 0m3.344s > user 0m0.053s > sys 0m0.374s > [jlayton@tlielax lockperf]$ time sudo ./opentest -n 128 -l 100 /mnt/rawhide/opentest > > real 0m3.550s > user 0m0.049s > sys 0m0.394s > > > ...so the speedup seems to be quite dramatic, actually -- 3x faster or > so with the patched kernel. > > The underlying filesystem is ext4 here, and the config is a rawhide > debug kernel config. For my next trick, I'll build some non-debug > kernels and replicate the test with them. Stay tuned... Just for grins, we should probably also try with the 3 client side OPEN parallelisation patches in my 'devel' branch. I'd expect them to give a slight performance improvement with your original test (i.e. the one that doesn't play the UID/GID games) Cheers Trond -- 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
