I tested the following kernels in tickless mode (CONFIG_NO_HZ=y), and they all contain the same load average reporting issue: 2.6.37-rc5-cure-more 2.6.39.4 3.2.2 3.2.4 Lesław, can you confirm that newer kernels still surface the bug in your environment? Aman On Fri, Feb 3, 2012 at 11:05 AM, Jonathan Nieder <jrnieder@gmail.com> wrote: > tags 620297 + upstream > quit > > Aman Gupta wrote: > >> Incorrect load average: >> 2.6.32-bpo.5-amd64 >> 2.6.32.55 >> 2.6.32.55-620297patch >> 2.6.32.55-620297patch (nohz=off) >> >> Correct load average: >> 2.6.32.55-620297patch (CONFIG_NO_HZ=n) >> >> Since CONFIG_NO_HZ=y is default on the debian kernels, the two >> upstream patches alone are not going to be enough to fix this issue. > > Thanks, Aman. So it looks like this will need more investigation. > > I assume kernels from sid do not have the same bug, right? If so, > here's a quick way to narrow the problem down, if you'd like. > > 1. Try the upstream kernel that introduced the "Cure more NO_HZ load > average woes" fix: > > cd linux > git checkout v2.6.37-rc7~13^2~5 > make silentoldconfig; # reuse configuration > make deb-pkg; # optionally with -j8 or so > dpkg -i ../<name of package> > reboot > > 2. Hopefully it does not reproduce the problem. So try its parent: > > cd linux > git checkout HEAD^ > make silentoldconfig; # reuse configuration > make -j8 deb-pkg > dpkg -i ../<name of package> > reboot > > Hopefully it reproduces the problem. > > If so, another test to try: > > cd linux > git checkout v2.6.35-rc1~521^2~16 > git cherry-pick -x -s v2.6.37-rc7~13^2~5 > make silentoldconfig > make -j8 deb-pkg > dpkg -i ../<name of package> > reboot > > If that also works fine, the problem was introduced in backporting the > fix from 2.6.35 to 2.6.32.y --- either it has a missing prerequisite, > or there might be some small textual error.
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