nfs-server to linux client.

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nfs-server to linux client.

Han Boetes
I suspect that this recent change in the nfs-code:

  http://www.openbsd.org/cgi-bin/cvsweb/src/sys/nfs/nfs_bio.c.diff?r1=1.40&r2=1.41

is causing troubles for my music listening. Especially flac files
have hickups. For a moment or a few seconds the stream is
interupted and then goes on again. But I am not absolutely sure.

When I change a window in my screen session I also often get a
similar hickup.

I was thinking of fragmentation, so I added a scrubline:

    scrub in on $int_if  all no-df

Since I have set rather large blocksizes to improve
throughput. Here is the fstab line for the Linux-client.

  haddock:/mnt/mp3 /mnt/mp3 nfs intr,rsize=16384,wsize=16384,nosuid,nodev,_netdev,nolock 0 0

Now the problem occurs less often, but it still happens.

So I tried to change the rsize and wsize to lower values and now
the problem is also gone:

  haddock:/mnt/mp3 /mnt/mp3 nfs intr,rsize=8192,wsize=8192,nosuid,nodev,_netdev,nolock 0 0

From the Linux manpage for nfs:

   Options
       rsize=n        The  number of bytes NFS uses when reading files from an
                      NFS server.  The default value is dependent on the  ker-
                      nel,  currently  1024  bytes.   (However,  throughput is
                      improved greatly by asking for rsize=8192.)

       wsize=n        The number of bytes NFS uses when writing  files  to  an
                      NFS  server.  The default value is dependent on the ker-
                      nel, currently  1024  bytes.   (However,  throughput  is
                      improved greatly by asking for wsize=8192.)

They are the blocksizes for reading and writing nfs packets.

But... 16384 has worked fine for ages. What has changed?



# Han

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Re: nfs-server to linux client.

Otto Moerbeek
On Fri, 18 Nov 2005, Han Boetes wrote:

> I suspect that this recent change in the nfs-code:
>
>   http://www.openbsd.org/cgi-bin/cvsweb/src/sys/nfs/nfs_bio.c.diff?r1=1.40&r2=1.41
>
> is causing troubles for my music listening. Especially flac files
> have hickups. For a moment or a few seconds the stream is
> interupted and then goes on again. But I am not absolutely sure.
[snip]

I would be surpised if the change to nfs_bio.c causes your trouble,
but did you try the obvious thing: backing out the change and
trying your original setup?

        -Otto

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Re: nfs-server to linux client.

Han Boetes
Otto Moerbeek wrote:

> On Fri, 18 Nov 2005, Han Boetes wrote:
>
> > I suspect that this recent change in the nfs-code:
> >
> >   http://www.openbsd.org/cgi-bin/cvsweb/src/sys/nfs/nfs_bio.c.diff?r1=1.40&r2=1.41
> >
> > is causing troubles for my music listening. Especially flac files
> > have hickups. For a moment or a few seconds the stream is
> > interupted and then goes on again. But I am not absolutely sure.
>
> I would be surpised if the change to nfs_bio.c causes your
> trouble, but did you try the obvious thing: backing out the
> change and trying your original setup?

You're right, that's not the problem.

Only bringing down the buffersize helps.



# Han

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Re: nfs-server to linux client.

Otto Moerbeek
On Sun, 20 Nov 2005, Han Boetes wrote:

> Otto Moerbeek wrote:
> > On Fri, 18 Nov 2005, Han Boetes wrote:
> >
> > > I suspect that this recent change in the nfs-code:
> > >
> > >   http://www.openbsd.org/cgi-bin/cvsweb/src/sys/nfs/nfs_bio.c.diff?r1=1.40&r2=1.41
> > >
> > > is causing troubles for my music listening. Especially flac files
> > > have hickups. For a moment or a few seconds the stream is
> > > interupted and then goes on again. But I am not absolutely sure.
> >
> > I would be surpised if the change to nfs_bio.c causes your
> > trouble, but did you try the obvious thing: backing out the
> > change and trying your original setup?
>
> You're right, that's not the problem.

Yes, as I expected; it's a client side change after all, and only
should affect reading files larger than 2G.

> Only bringing down the buffersize helps.

A few questions/things to try to:

- Did the linux client change?

- Try running a 3.8-release kernel to see if it is a recent
regression.

        -Otto

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Re: nfs-server to linux client.

Han Boetes
Otto Moerbeek wrote:
> On Sun, 20 Nov 2005, Han Boetes wrote:
> > Only bringing down the buffersize helps.
>
> A few questions/things to try to:
>
> - Did the linux client change?
>
> - Try running a 3.8-release kernel to see if it is a recent
>   regression.

Looking a bit deeper into the problem I noticed that the
data-transfer rates over ftp are also miserable.

The connection is a x-cable between two re gigabit cards and I get
a transferrate of 1mb/s, which used to be about 8mb/s, the
speedlimit of the harddrives.

So something bad is going on here. I just have to dig more. But
not today anymore.



# Han