All benchmark runs are using a fixed-size dataset over different op/s
values, to avoid filling the disk at high throughput.


knfsd-sync:
Linux in-kernel NFS server, exported with the 'sync' option.

knfsd-async:
Same as above, but using the 'async' option so that writes need not be
on disk before replying to a client.

bluesky:
Initial testing with the Bluesky proxy, storing data to kvstore on a
local network (not to S3).