8/18/2017 · There are two system-level workqueues that run in this mode as well: system_power_efficient_wq and system_freezable_power_efficient_wq; they can be used when a private workqueue is not needed. Instead of running work on the local CPU, the workqueue core asks the scheduler to provide the target CPU for the work queued on unbound workqueues (which includes.
4/23/2020 · system_freezable _power_ efficient _wq can still try to submit SCSI commands and this can cause a panic since the low level SCSI driver (e.g. hv_storvsc).
* system_freezable_wq is equivalent to system_wq except that it’s * freezable. + * + * *_power_efficient_wq are inclined towards saving power and converted + * into WQ_UNBOUND variants if ‘wq_power_efficient’ is enabled; otherwise, + * they are same as their non-power-efficient counterparts – e.g. + * system_power_efficient_wq is identical to system_wq if, * freezable. * * *_power_efficient_wq are inclined towards saving power and converted * into WQ_UNBOUND variants if ‘wq_power_efficient’ is enabled; otherwise, * they are same as their non-power-efficient counterparts – e.g. * system_power_efficient_wq is identical to system_wq if * ‘wq_power_efficient’ is disabled. See WQ_POWER_EFFICIENT for more info. */, – Created few system wide workqueues aligned towards power saving. V3->V4: —– – Dropped changes to kernel/sched directory and hence sched_select_non_idle_cpu(). – Dropped queue_work_on_any_cpu() – Created system _ freezable _unbound_wq – Changed all patches accordingly.
Block layer uses workqueues for multiple purposes. There is no real dependency of scheduling these on the cpu which scheduled them. On a idle system , it is observed that and idle cpu wakes up many times just to service this work.
12/9/2019 · > – The original devfreq_wq include the only work related to devfreq. > – system_freezable_power_efficient_wq include the all works registered > from both other subsystem and device drivers in linux kernel. I do not know that good system wq, devfreq_wq have only one work item so imho it is not beneficial to use separate wq.
extern struct workqueue_struct * system_freezable _power_ efficient _wq; -extern bool wq_online; – extern struct workqueue_struct * __alloc_workqueue_key(const char *fmt, unsigned int flags, int max_active, …
Block layer uses workqueues for multiple purposes. There is no real dependency of scheduling these on the cpu which scheduled them. On a idle system , it is observed that and idle cpu wakes up many times just to service this work. It would be better if we can schedule it on a cpu which the scheduler believes to be the most appropriate one. This patch replaces normal workqueues with power …
drivers are found to be very much active on idle or lightly busy system and using WQ_POWER_EFFICIENT for these gave impressive results. These would be used in power saving mode only if relevant configs are enabled
