Commits
Youquan Song committed e11538d1f03
cpuidle: Quickly notice prediction failure in general case The prediction for future is difficult and when the cpuidle governor prediction fails and govenor possibly choose the shallower C-state than it should. How to quickly notice and find the failure becomes important for power saving. The patch extends to general case that prediction logic get a small predicted residency, so it choose a shallow C-state though the expected residency is large . Once the prediction will be fail, the CPU will keep staying at shallow C-state for a long time. Acutally, the CPU has change enter into deep C-state. So when the expected residency is long enough but governor choose a shallow C-state, an timer will be added in order to monitor if the prediction failure. When C-state is waken up prior to the adding timer, the timer will be cancelled initiatively. When the timer is triggered and menu governor will quickly notice prediction failure and re-evaluates deeper C-states possibility. Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Youquan Song <youquan.song@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>