Re: Why is NFSv4 so slow?

On Mon, Jun 28, 2010 at 12:35:14AM -0400, Rick Macklem wrote:

Being stuck in "newnfsreq" means that it is trying to establish a TCP
connection with the server (again smells like some networking issue).
Disabling delegations is the next step. (They aren't
required for correct behaviour and are disabled by default because
they are the "greenest" part of the implementation.)

After disabling delegations, I was able to build world and kernel on two
different clients, and my port build problems went away as well.

I'm still left with a performance problem, although not quite as bad as I
originally reported. Directory listings are snappy once again, but playing
h264 video is choppy, particularly when seeking around: there's almost a
full second delay before it kicks in, no matter where I seek. With NFSv3
the delay on seeks was less than 0.1 seconds and the playback was never

I can try it again with v3 client and v4 server, if you think that's
worthy of pursuit. If it makes any difference, the server's four CPUs are
pegged at 100% (running "nice +4" cpu-bound jobs). But that was the case
before I enabled v4 server too.

-- Rick C. Petty
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