On Mon 2022-04-25 16:21 -0300, Marcelo Tosatti wrote: > > Hi Peter, Christoph, > > > > Indeed. Which was why I decided, initially, against the general-purpose > > case/or approach. Personally, I would prefer to keep this somewhat > > restrictive to nohz. > > Is there anything that prevents a nohz full CPU from running an > application with short and frequent idling? Hi Marcelo, I'm not sure I understand the question; albeit, if I understand correctly, yes: the scheduling-clock tick, if it was stopped. Yet I believe this behaviour is correct. Consider the following example: When a CFS task is moved/or migrated to a nohz_full CPU that was previously idle and had its tick stopped, if its the only task on the run-queue then it is possible that the idle task may not restart the tick (see __tick_nohz_full_update_tick()). Thus once the CFS task exits manual intervention i.e. a reschedule IPI to wake the idle task, would be required to run again, on the same CPU. Kind regards, -- Aaron Tomlin
