Messages in this thread | ![/](/images/icornerl.gif) | | Subject | Re: High CPU load when machine is idle (related to PROBLEM: Unusually high load average when idle in 2.6.35, 2.6.35.1 and later) | From | Peter Zijlstra <> | Date | Mon, 29 Nov 2010 12:38:46 +0100 |
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On Sun, 2010-11-28 at 12:40 +0100, Damien Wyart wrote: > Hi, > > * Peter Zijlstra <peterz@infradead.org> [2010-11-27 21:15]: > > How does this work for you? Its hideous but lets start simple. > > [...] > > Doesn't give wrong numbers like initial bug and tentative patches, but > feels a bit too slow when numbers go up and down. Correct values are > reached when waiting long enough, but it feels slow. > > As I've tested many combinations, maybe this is an impression because > I do not remember about "normal" delays for the load to rise and fall, > but this still feels slow.
You can test this by either booting with nohz=off, or builting with CONFIG_NO_HZ=n and then comparing the result, something like
make O=defconfig clean; while sleep 10; do uptime >> load.log; done & make -j32 O=defconfig; kill %1
And comparing the curves between the NO_HZ and !NO_HZ kernels.
I'll try and make the patch less hideous ;-)
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