Subject: Re: nfsio behaviour on 2.0F
To: Stephen M. Jones <email@example.com>
From: Nathan J. Williams <firstname.lastname@example.org>
Date: 07/14/2004 14:48:01
"Stephen M. Jones" <email@example.com> writes:
> directory. When I do this with two CS20s running FreeBSD 5.2.1, I do not
> generate a load over 1.00 and I do not experience ethernet timeouts.
You don't actually say so, but does this imply that you do see
timeouts on NetBSD?
> However, within a few hours of doing the same excerise using a NetBSD 2.0F
> client writing to the NFS mounted filesystem I have a process table that
> looks like this:
[four [nfsio]'s with about 3:40 time each, load 4.8]
> The CS20 running FreeBSD 5.2.1 is SMP however and has a proc table that looks
> like this:
[five nfsd's with more varying time, load 0.02]
> I can probably kill off the nfsio processes and bring the load down, but
> my question is, why is it happening? When I have the scenario reversed
> you might find it interesting that FreeBSD as a client has delays (nfsrcvlk)
> during simple operations such as 'cat' and 'ls' while the 500mb file is
> being created. When NetBSD is the client 'cat' and 'ls' are pretty snappy.
Is the load number a problem? Is the system otherwise less responsive?
I think you're seeing artifacts of how load is measured on the two
systems, and a more round-robin distribution of NFS tasks to kernel
threads in the case of NetBSD. In other words, a somewhat
apples-to-oranges comparison. You need to find a benchmark result you
care about, and measure that.