Re: NFS client (10x) performance regression 2.6.14.7 -> 2.6.15

[Jakob Oestergaard <jakob@unthought.net>]

On Fri, Mar 31, 2006 at 10:04:53AM -0500, Bill Rugolsky Jr. wrote:
> On Fri, Mar 31, 2006 at 04:57:26PM +0200, Jakob Oestergaard wrote:
> > True. But it is my impression that this is a problem isolated on the
> > client side (am I wrong?)
> 
> That seems to be the case.

Hmm...

> 
> > Do you mean NFS exporting a local filesystem, NFS mounting it again on
> > the local host?   Or do you mean something with loopback mounts?
>  
> The former; just export a local directory to 127.0.0.1 in /etc/exports,
> then mount it on /mnt.

With a local export/mount I see very few reads running the test  :/

Could this be a timing issue?  That pages in the cache are invalidated
after maybe less than 100 microseconds which is roughly the round-trip
time on the gigabit network connecting my server and client?

/proc/self/mountstats on the two filesystems look identical to me:

device sparrow:/exported/joe mounted on /u/joe with fstype nfs statvers=1.0
opts: rw,vers=3,rsize=32768,wsize=32768,acregmin=3,acregmax=60,
      acdirmin=30,acdirmax=60,hard,intr,proto=udp,timeo=7,retrans=3

device localhost:/home/test mounted on /mnt with fstype nfs statvers=1.0
opts: rw,vers=3,rsize=32768,wsize=32768,acregmin=3,acregmax=60,
      acdirmin=30,acdirmax=60,hard,intr,proto=udp,timeo=7,retrans=3


-- 

 / jakob