On Sun, 8 Jun 2003, Richard Rauch wrote:

> On Sun, Jun 08, 2003 at 11:56:45AM +0100, David Brownlee wrote:
> > 	You might want to try mounting the nfs filesystem with an 8k or
> > 	16k block size rather than the (i386) default of 32k.
> >
> > 	mount_nfs -r 8192 remote:/dir /local_dir
>
> This (and dropping the TCP option) seems to have helped.  (Some time ago,
> I received the impression that TCP mounts were friendlier and that the
> original impetus for UDP mounts was no longer appropriate, so I was just
> using TCP...)
>
	TCP will certainly handle dropped packets more gracefully.

> Telling the driver that the chipset only has 8KB seemed to increase the
> number of overruns per unit time ("Message repeated ??? times..."), but
> virtually elminated the audible glitches in XMMS playing of .ogg files.
> (This was before receiving the above suggestion.)

	I would expect to see more errors with a smaller buffer. I'm
	surprised it works better though...

> Is this just a fact of life that you sometimes need to do this with
> NFS and some cards, or does it suggest a driver problem?  The card was
> not the first one that I tried, but it was the first one that that I
> tried and that *worked* with NetBSD.

	NetBSD (probably from 1.6, though maybe earlier) defaults to
	a 32K blocksize on NFS (certainly on i386). This is pretty
	much guaranteed to lose on any card with less than 32K (*)
	if the remote machine is capable of sending data faster than
	the receiving host can handle an interrupt and pull the data
	off the card. Obviously this is much worse on a slow bus like
	pcmcia.

	(*) technically 32K is not enough to handle 32K packets as
	extra memory will be used for packet headers and other data

	It would be helpful if the mount_nfs manpage had a section
	explaining all this. Care to suggest some text? :)

-- 
		David/absolute          -- www.netbsd.org: No hype required --