On 26-01-17, 11:15, Joel Fernandes wrote:
Some possibly naive questions about this patch, when you say "system is configured such that new tasks should receive maximum demand", do you mean an RT task waking up on a remote CPU or do you mean in general? Can you clarify how/where this configuration for new tasks is done?
I think Steve (who wrote this stuff initially) wanted to say that in a general way. We don't have any such configurable way possible right now, but there were discussions on how much utilization should a new task be assigned when it first comes up.
Also, if new tasks are not to receive maximum demand initially (as you
This stuff shall help for all the ranges I hope, not just for maximum demands initially. Its just that the CPU may be running at an OPP much lower than what the task may want initially. Without this patch we will wait for a tick's time to raise it up.
indicated its configurable), then shouldn't the late cpufreq callbacks never happen for the cases where new tasks are not to receive maximum demand? With these patches they always will invoke the late callbacks? In this case the currently running task on the remote CPU should already have brought the demand levels to a high value, then in that case should the callbacks run? I was just wondering if we can avoid unwanted IPIs from this patch in that case.
The IPI isn't sent always. We send it only if its been long since we last evaluated freq change and current rq load wants us to change the frequency.
-- viresh