freebsd stable - Jul 2014 - 9-STABLE nfsd(8) does not auto-tune number of threads (error in the 9.3 Release Notes!)

One of the 9.3-RELEASE Release Notes (userland changes) states that:

"The default number of nfsd(8) threads has been increased from 4 to (8 *
N), where N is the number of CPUs as reported by sysctl -n hw.ncpu.
[r262124]"

Indeed, revision r262124
(http://svnweb.freebsd.org/base?view=revision&revision=262124) removes the
"-n 4" option from nfs_server_flags in /etc/defaults/rc.conf.

The change is based on the premise that nfsd(8) auto-tunes the number of threads
as (8 * hw.ncpu). That auto-tuning was introduced in HEAD revision r243637 of
nfsd.c (http://svnweb.freebsd.org/base?view=revision&revision=243637), but
it has not been MFC'd to 9-STABLE yet, so that release note *is not true*.

I think that r262124 should be reverted, also removing the release note
mentioned above; or alternatively bring HEAD's nfsd.c on sync with 9-STABLE
(probably a bad idea just before 9.3-RELEASE).


Greetings,

--
Jos? M. Alcaide
Universidad del Pa?s Vasco
Dpto. de Electricidad y Electr?nica
Facultad de Ciencia y Tecnolog?a
48940 Leioa (Spain)

On Tue, Jul 08, 2014 at 03:06:38PM +0200, Jos? Mar?a Alcaide
wrote:
> One of the 9.3-RELEASE Release Notes (userland changes) states that:
> 
> "The default number of nfsd(8) threads has been increased from 4 to (8
* N), where N is the number of CPUs as reported by sysctl -n hw.ncpu.
[r262124]"
> 
> Indeed, revision r262124
(http://svnweb.freebsd.org/base?view=revision&revision=262124) removes the
"-n 4" option from nfs_server_flags in /etc/defaults/rc.conf.
> 
> The change is based on the premise that nfsd(8) auto-tunes the number of
threads as (8 * hw.ncpu). That auto-tuning was introduced in HEAD revision
r243637 of nfsd.c
(http://svnweb.freebsd.org/base?view=revision&revision=243637), but it has
not been MFC'd to 9-STABLE yet, so that release note *is not true*.
> 
> I think that r262124 should be reverted, also removing the release note
mentioned above; or alternatively bring HEAD's nfsd.c on sync with 9-STABLE
(probably a bad idea just before 9.3-RELEASE).
> 
Reverting r262124 is also not an option at this point of the release
cycle.

Rick, do you have any reservations to issuing an errata notice for this
after the release?

Glen

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