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SubjectRe: nfs slowdown since 2.5.4
On Tuesday 04 June 2002 14:23, Trond Myklebust wrote:
> >>>>> " " == Matthias Welk <> writes:
> > Hi, since 2.5.4 I noticed a big slowdown in nfs. It seems that
> > this is related to the changes in the nfs-lookup code, because
> > now most traffic via nfs is for lookup- and getattr-calls as
> > you can see in the attached tcpdump log. I'v also attached a
> > log of nfsstat, which shows this problem too.
> Tough... Those extra checks are needed in order to ensure data cache
> correctness on file open().
> If you think you don't need them because the files that you are
> reading are known never to change on the server, you can try mounting
> with the 'nocto' mount option.

I tried again with the 'nocto' mount option, although I can't be sure that the
files will not change on the server, but the behaviour didn't change :-(

To get more info about this problem I compared the compile time and the nfs
traffic between 2.4.18-4 and 2.5.20 on a RedHat 7.3 system.
The sources (mosfet-liquid0.9.5.tar.gz - KDE style) were located on the local
disc and the libraries were linked over nfs.
The results attached to this mail show the big difference !

I hope you can do anything with it.

Greetings, Matthias.
From: Matthias Welk office: +49-30-3463-7272
FHG Fokus mobile: +49-179- 1144752
Kaiserin-Augusta-Allee 31 fax : +49-30-3463-8672
10589 Berlin email :

#time to build on a RedHat 7.3 system with 2.4.18-4

real 1m1.301s
user 0m50.920s
sys 0m8.390s

lookup: 2820
getattr: 22
readdir: 96
frag: 66#time to build on a RedHat 7.3 system with 2.5.20

real 1m48.509s
user 0m51.320s
sys 0m12.790s

lookup: 287582
getattr: 2546
readdir: 1958
frag: 8465
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