No, I think it is a bug.
Because I tested the option with NO_HZ_FULL and without NO_HZ_FULL_ALL. It had only little interruptes on CPU0 twd. With same code, I added NO_HZ_FULL_ALL option. It had too many interruptes on CPU0 twd.
So the sumbitter just didn't test twd interrupts, when he expanded NO_HZ_FULL option to all cpu.
On Thu, Nov 14, 2013 at 4:09 PM, viresh kumar viresh.kumar@linaro.org 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