[Bug 1071978] Re: nfs kernel server is very slow and causing high cpu load

[Tim]

yes it is over a gigabit link.

Once I hit a hangup IO drops right off to around 1MB/s

procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
 r b swpd free buff cache si so bi bo in cs us sy id wa
1  0 2490892 112292  87920 807736    0    0     0  1520 1689 2452  1  1 53 45
 1  1 2490892 110960  87920 808820    0    0     0  1672 1831 2632  2  2 50 47
 1  1 2490892 110340  87920 809580    0    0     0  1384 1551 2213  1  1 51 47
 1  1 2490892 109440  87936 810288    0    0     0  1388 1548 2390  2  1 45 52
 1  6 2490892 108572  87944 811148    0    0     0  1472 1555 2298  2  2 49 47

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https://bugs.launchpad.net/bugs/1071978

Title:
  nfs kernel server is very slow and causing high cpu load

Status in “nfs-utils” package in Ubuntu:
  New

Bug description:
  I have been noticing nfs-kernel server causing very high cpu load and
  the transfers are incredibly slow. In fact for big files, it tends to
  hang up completely and never finish.

  I did try briefly to test the 3.5 backport kernel however that also
  seemed to have the same issue.

  This may be a duplication of bug #879334, however that bug is missing
  log files, and apport-collect told me to file a new bug report
  instead.

  ProblemType: Bug
  DistroRelease: Ubuntu 12.04
  Package: nfs-kernel-server 1:1.2.5-3ubuntu3.1
  ProcVersionSignature: Ubuntu 3.2.0-32.51-generic 3.2.30
  Uname: Linux 3.2.0-32-generic x86_64
  ApportVersion: 2.0.1-0ubuntu14
  Architecture: amd64
  Date: Sat Oct 27 14:50:09 2012
  InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Beta amd64 (20120328)
  ProcEnviron:
   LANGUAGE=en_AU:en
   TERM=xterm
   PATH=(custom, no user)
   LANG=en_AU.UTF-8
   SHELL=/bin/bash
  SourcePackage: nfs-utils
  UpgradeStatus: No upgrade log present (probably fresh install)

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