Messages in this thread |  | | Date | Tue, 14 Apr 2015 11:54:24 +0200 | From | Peter Zijlstra <> | Subject | Re: load average always more then 1 on idle system with dyntick (just after boot) |
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On Tue, Mar 31, 2015 at 10:52:48PM +0300, Azat Khuzhin wrote: > Hi all, > > On one of machines [SUPERMICRO], after installing fresh kernel > (v4.0-rc5-25-g90a5a89), I noticed that loadavg always greater then 1. > > I do a lot of digging and finally have more information on this issue: > CONFIG_NO_HZ_IDLE=y # loadavg always > 1 > CONFIG_HZ_PERIODIC=y # loadavg < 1 > > After this I tried to disable "nohz" at boot, to determine whether it is > statically added code under #ifdef during compilation or not, so I added > "nohz=off" to cmdline, and it helps! > > Also if you enable preemption loadavg is also < 1: > CONFIG_PREEMPT_VOLUNTARY=y
So you need CONFIG_PREEMPT=n and CONFIG_NO_HZ_IDLE=y for this to happen?
That's somewhat odd (and uncommon I think, most everybody has at least VOLUNTARY enabled these days).
I'll try to look over the code to see if I can find a preempt relation, weird that.
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