Slow SMB performance over GVFS

[Will Rouesnel <w rouesnel gmail com>]

Copying with Windows 7 to my Ubuntu 13.04 file server running ZFS, I can
achieve upwards of 80mb/s transfer speeds, with a minimum of maybe 60
mb/s on a bad day (this is with a couple of large files).

Doing the same operation with GVFS, I'm lucky to clear 20 mb/s (27-28 is
the highest I've seen).

Doing the same operation with rsync -W and the GVFS mounts, I get no
more then 1mb/s (Same with dd).

Doing the same operation with rsync over ssh, I get ~50 mb/s.

If I run the same operation a few times (to account for a warmed cache),
rsync -W (i.e. no deltas) leaps to 100 mb/s (line-speed essentially),
while GVFS Samba will chug at about 50 mb/s.

This to me seems like a ridiculous state of affairs on the desktop. I'd
really love to know where to look to either tweak things for improved
speed or to help debug this issue.

While technically I can plan my file operations to work around GVFS, it
really shouldn't be when in Windows I can point an application at a
network share and expect things to work out fine (thus the point of me
having a fileserver) whereas currently on my desktop I have to dance
around mounting and unmounting things and hoping it'll work out.