Poor NFS server performance in 6.0 with SMP and mpsafenet=1

[Gavin Atkinson]

On Wed, 2005-11-02 at 16:23 +0100, Bernd Walter wrote:
> On Wed, Nov 02, 2005 at 02:58:36PM +0000, Gavin Atkinson wrote:
> > I'm seeing incredibly poor performance when serving files from an SMP
> > FreeBSD 6.0RC1 server to a Solaris 10 client.  I've done some
> > experimenting and have discovered that either removing SMP from the
> > kernel, or setting debug.mpsafenet=0 in loader.conf massively improves
> > the speed.  Switching preemption off seems to also help.
> > 
> > No SMP, mpsafenet=1			 59.4
> > No SMP, mpsafenet=0			 49.4
> > No SMP, mpsafenet=1, no PREEMPTION	 53.1
> > No SMP, mpsafenet=0, no PREEMPTION	 51.9
> >    SMP, mpsafenet=1			351.7
> >    SMP, mpsafenet=0			 74.5
> >    SMP, mpsafenet=1, no PREEMPTION	264.9
> >    SMP, mpsafenet=0, no PREEMPTION	 53.7
> 
> Which scheduler?

BSD.  As I say, I'm running 6.0-RC1 with the standard GENERIC kernel,
apart from the options I have listed as being changed above.  Polling is
therefore also not enabled.

When I get home, I'll have a play with both ULE and POLLING to see what
difference they make, however ideally I'd like to not use polling in
production if possible.

Gavin