kernel/linux.git/include/linux/energy_model.h, branch v6.12.80

PM: EM: Fix incorrect description of the cost field in struct em_perf_state

2026-01-23T10:18:36+00:00

[ Upstream commit 54b603f2db6b95495bc33a8f2bde80f044baff9a ] Due to commit 1b600da51073 ("PM: EM: Optimize em_cpu_energy() and remove division"), the logic for energy consumption calculation has been modified. The actual calculation of cost is 10 * power * max_frequency / frequency instead of power * max_frequency / frequency. Therefore, the comment for cost has been updated to reflect the correct content. Fixes: 1b600da51073 ("PM: EM: Optimize em_cpu_energy() and remove division") Signed-off-by: Yaxiong Tian Reviewed-by: Lukasz Luba [ rjw: Added Fixes: tag ] Link: https://patch.msgid.link/20251230061534.816894-1-tianyaxiong@kylinos.cn Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin

PM: EM: Address RCU-related sparse warnings

2025-05-02T05:58:52+00:00

[ Upstream commit 3ee7be9e10dd5f79448788b899591d4bd2bf0c19 ] The usage of __rcu in the Energy Model code is quite inconsistent which causes the following sparse warnings to trigger: kernel/power/energy_model.c:169:15: warning: incorrect type in assignment (different address spaces) kernel/power/energy_model.c:169:15: expected struct em_perf_table [noderef] __rcu *table kernel/power/energy_model.c:169:15: got struct em_perf_table * kernel/power/energy_model.c:171:9: warning: incorrect type in argument 1 (different address spaces) kernel/power/energy_model.c:171:9: expected struct callback_head *head kernel/power/energy_model.c:171:9: got struct callback_head [noderef] __rcu * kernel/power/energy_model.c:171:9: warning: cast removes address space '__rcu' of expression kernel/power/energy_model.c:182:19: warning: incorrect type in argument 1 (different address spaces) kernel/power/energy_model.c:182:19: expected struct kref *kref kernel/power/energy_model.c:182:19: got struct kref [noderef] __rcu * kernel/power/energy_model.c:200:15: warning: incorrect type in assignment (different address spaces) kernel/power/energy_model.c:200:15: expected struct em_perf_table [noderef] __rcu *table kernel/power/energy_model.c:200:15: got void *[assigned] _res kernel/power/energy_model.c:204:20: warning: incorrect type in argument 1 (different address spaces) kernel/power/energy_model.c:204:20: expected struct kref *kref kernel/power/energy_model.c:204:20: got struct kref [noderef] __rcu * kernel/power/energy_model.c:320:19: warning: incorrect type in argument 1 (different address spaces) kernel/power/energy_model.c:320:19: expected struct kref *kref kernel/power/energy_model.c:320:19: got struct kref [noderef] __rcu * kernel/power/energy_model.c:325:45: warning: incorrect type in argument 2 (different address spaces) kernel/power/energy_model.c:325:45: expected struct em_perf_state *table kernel/power/energy_model.c:325:45: got struct em_perf_state [noderef] __rcu * kernel/power/energy_model.c:425:45: warning: incorrect type in argument 3 (different address spaces) kernel/power/energy_model.c:425:45: expected struct em_perf_state *table kernel/power/energy_model.c:425:45: got struct em_perf_state [noderef] __rcu * kernel/power/energy_model.c:442:15: warning: incorrect type in argument 1 (different address spaces) kernel/power/energy_model.c:442:15: expected void const *objp kernel/power/energy_model.c:442:15: got struct em_perf_table [noderef] __rcu *[assigned] em_table kernel/power/energy_model.c:626:55: warning: incorrect type in argument 2 (different address spaces) kernel/power/energy_model.c:626:55: expected struct em_perf_state *table kernel/power/energy_model.c:626:55: got struct em_perf_state [noderef] __rcu * kernel/power/energy_model.c:681:16: warning: incorrect type in assignment (different address spaces) kernel/power/energy_model.c:681:16: expected struct em_perf_state *new_ps kernel/power/energy_model.c:681:16: got struct em_perf_state [noderef] __rcu * kernel/power/energy_model.c:699:37: warning: incorrect type in argument 2 (different address spaces) kernel/power/energy_model.c:699:37: expected struct em_perf_state *table kernel/power/energy_model.c:699:37: got struct em_perf_state [noderef] __rcu * kernel/power/energy_model.c:733:38: warning: incorrect type in argument 3 (different address spaces) kernel/power/energy_model.c:733:38: expected struct em_perf_state *table kernel/power/energy_model.c:733:38: got struct em_perf_state [noderef] __rcu * kernel/power/energy_model.c:855:53: warning: dereference of noderef expression kernel/power/energy_model.c:864:32: warning: dereference of noderef expression This is because the __rcu annotation for sparse is only applicable to pointers that need rcu_dereference() or equivalent for protection, which basically means pointers assigned with rcu_assign_pointer(). Make all of the above sparse warnings go away by cleaning up the usage of __rcu and using rcu_dereference_protected() where applicable. Cc: All applicable Signed-off-by: Rafael J. Wysocki Reviewed-by: Lukasz Luba Link: https://patch.msgid.link/5885405.DvuYhMxLoT@rjwysocki.net Signed-off-by: Sasha Levin

PM: EM: Add em_dev_update_chip_binning()

2024-04-08T14:05:14+00:00

Add a function which allows to modify easily the EM after the new voltage information is available. The device drivers for the chip can adjust the voltage values after setup. The voltage for the same frequency in OPP can be different due to chip binning. The voltage impacts the power usage and the EM power values can be updated to reflect that. Reviewed-by: Dietmar Eggemann Signed-off-by: Lukasz Luba Signed-off-by: Rafael J. Wysocki

PM: EM: fix wrong utilization estimation in em_cpu_energy()

2024-04-04T17:27:53+00:00

Commit 1b600da51073 ("PM: EM: Optimize em_cpu_energy() and remove division") has added back map_util_perf() in em_cpu_energy() computation which has been removed with the rework of scheduler/cpufreq interface. This is wrong because sugov_effective_cpu_perf() already takes care of mapping the utilization to a performance level. Fixes: 1b600da51073 ("PM: EM: Optimize em_cpu_energy() and remove division") Signed-off-by: Vincent Guittot Reviewed-by: Lukasz Luba Signed-off-by: Rafael J. Wysocki

PM: EM: Add em_dev_compute_costs()

2024-02-08T14:00:32+00:00

The device drivers can modify EM at runtime by providing a new EM table. The EM is used by the EAS and the em_perf_state::cost stores pre-calculated value to avoid overhead. This patch provides the API for device drivers to calculate the cost values properly (and not duplicate the same code). Reviewed-by: Dietmar Eggemann Tested-by: Dietmar Eggemann Signed-off-by: Lukasz Luba Signed-off-by: Rafael J. Wysocki

PM: EM: Remove old table

2024-02-08T14:00:32+00:00

Remove the old EM table which wasn't able to modify the data. Clean the unneeded function and refactor the code a bit. Reviewed-by: Dietmar Eggemann Tested-by: Dietmar Eggemann Signed-off-by: Lukasz Luba Signed-off-by: Rafael J. Wysocki

PM: EM: Optimize em_cpu_energy() and remove division

2024-02-08T14:00:31+00:00

The Energy Model (EM) can be modified at runtime which brings new possibilities. The em_cpu_energy() is called by the Energy Aware Scheduler (EAS) in its hot path. The energy calculation uses power value for a given performance state (ps) and the CPU busy time as percentage for that given frequency. It is possible to avoid the division by 'scale_cpu' at runtime, because EM is updated whenever new max capacity CPU is set in the system. Use that feature and do the needed division during the calculation of the coefficient 'ps->cost'. That enhanced 'ps->cost' value can be then just multiplied simply by utilization: pd_nrg = ps->cost * \Sum cpu_util to get the needed energy for whole Performance Domain (PD). With this optimization and earlier removal of map_util_freq(), the em_cpu_energy() should run faster on the Big CPU by 1.43x and on the Little CPU by 1.69x (RockPi 4B board). Reviewed-by: Dietmar Eggemann Tested-by: Dietmar Eggemann Signed-off-by: Lukasz Luba Signed-off-by: Rafael J. Wysocki

PM: EM: Add performance field to struct em_perf_state and optimize

2024-02-08T14:00:31+00:00

The performance doesn't scale linearly with the frequency. Also, it may be different in different workloads. Some CPUs are designed to be particularly good at some applications e.g. images or video processing and other CPUs in different. When those different types of CPUs are combined in one SoC they should be properly modeled to get max of the HW in Energy Aware Scheduler (EAS). The Energy Model (EM) provides the power vs. performance curves to the EAS, but assumes the CPUs capacity is fixed and scales linearly with the frequency. This patch allows to adjust the curve on the 'performance' axis as well. Code speed optimization: Removing map_util_freq() allows to avoid one division and one multiplication operations from the EAS hot code path. Reviewed-by: Dietmar Eggemann Tested-by: Dietmar Eggemann Signed-off-by: Lukasz Luba Signed-off-by: Rafael J. Wysocki

PM: EM: Add em_perf_state_from_pd() to get performance states table

2024-02-08T14:00:31+00:00

Introduce a wrapper to get the performance states table of the performance domain. The function should be called within the RCU read critical section. Reviewed-by: Dietmar Eggemann Tested-by: Dietmar Eggemann Signed-off-by: Lukasz Luba Signed-off-by: Rafael J. Wysocki

PM: EM: Introduce em_dev_update_perf_domain() for EM updates

2024-02-08T14:00:30+00:00

Add API function em_dev_update_perf_domain() which allows the EM to be changed safely. Concurrent updaters are serialized with a mutex and the removal of memory that will not be used any more is carried out with the help of RCU. Reviewed-by: Dietmar Eggemann Tested-by: Dietmar Eggemann Signed-off-by: Lukasz Luba Signed-off-by: Rafael J. Wysocki