14 Nov
2013
14 Nov
'13
11:42 a.m.
On Thu, Nov 14, 2013 at 01:39:43PM +0530, viresh kumar wrote:
On Thursday 14 November 2013 01:35 PM, Vincent Guittot wrote:
AFAICT, It's a none issue. In full nohz, a timer fires periodically (around 4sec period on ARM IIRC) on one cpu (cpu0).
Timer should always be running on CPU0, its out of nohz-full domain. Its cpu 1, where it will fire after long delays..
https://wiki.linaro.org/WorkingGroups/PowerManagement/Doc/AdaptiveTickless
Right. CPU 0 stays pure periodic unless you select CONFIG_NO_HZ_FULL_SYSIDLE=y then it can be also nohz when the full system is idle. I strongly recommend for power consumption.