On Tue, Apr 14, 2015 at 11:54:24AM +0200, Peter Zijlstra wrote: > 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?
Yep, CONFIG_PREEMPT_NONE=y and CONFIG_NO_HZ_IDLE=y > That's somewhat odd (and uncommon I think, most everybody has at least > VOLUNTARY enabled these days). This is not a big problem for me, I could enable VOLUNTARY, but I don't think that it will be useful for my workload. But I could be wrong. > I'll try to look over the code to see if I can find a preempt relation, > weird that. Thanks! -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
