slow loop performance.

Hi!

Great job with NFS server, it surely is fast, but not on loop devices.

If I loop mount a file and share the mount point over NFS3 or NFS4, the write performance of the client on the loop mounted share is pretty bad.

On a 100 Mbps (or 12.5MBps) full duplex Ethernet link, I get ~8MBps speeds, whereas on the loop mounted device, I get at best 6MBps.

Any ideas why?

My server configuration (NFS4) -- anonuid=1000,anongid=1000,secure,no_subtree_check,rw,fsid=0,crossmnt

My client mount options -- rsize=1048576,wsize=1048576,async,hard,timeo=60,retrans=2,actimeo=900,retry=2,lookupcache=pos,nfsvers=4,nolock,intr,noacl,rdirplus