pm: policy: default: Optimize power state selection (bb4fb12c) · Commits · Wenxi XU / zephyr

subsys/pm/policy/policy_default.c

+13 −18

Changes for subsys/pm/policy/policy_default.c: 13 added lines, 18 removed lines.
Original line number	Diff line number	Diff line
		@@ -9,13 +9,12 @@
		#include <zephyr/sys_clock.h>
		#include <zephyr/pm/device.h>

		extern int32_t max_latency_cyc;

		const struct pm_state_info *pm_policy_next_state(uint8_t cpu, int32_t ticks)
		{
		int64_t cyc = -1;
		uint8_t num_cpu_states;
		const struct pm_state_info *cpu_states;
		const struct pm_state_info *out_state = NULL;

		#ifdef CONFIG_PM_NEED_ALL_DEVICES_IDLE
		if (pm_device_is_any_busy()) {
		@@ -29,29 +28,25 @@ const struct pm_state_info *pm_policy_next_state(uint8_t cpu, int32_t ticks)

		num_cpu_states = pm_state_cpu_get_all(cpu, &cpu_states);

		for (int16_t i = (int16_t)num_cpu_states - 1; i >= 0; i--) {
		for (uint32_t i = 0; i < num_cpu_states; i++) {
		const struct pm_state_info *state = &cpu_states[i];
		uint32_t min_residency_cyc, exit_latency_cyc;
		uint32_t min_residency_ticks;

		/* check if there is a lock on state + substate */
		if (pm_policy_state_lock_is_active(state->state, state->substate_id)) {
		continue;
		}
		min_residency_ticks =
		k_us_to_ticks_ceil32(state->min_residency_us + state->exit_latency_us);

		min_residency_cyc = k_us_to_cyc_ceil32(state->min_residency_us);
		exit_latency_cyc = k_us_to_cyc_ceil32(state->exit_latency_us);
		if (ticks < min_residency_ticks) {
		/* If current state has higher residency then use the previous state; */
		break;
		}

		/* skip state if it brings too much latency */
		if ((max_latency_cyc >= 0) &&
		(exit_latency_cyc >= max_latency_cyc)) {
		/* check if state is available. */
		if (!pm_policy_state_is_available(state->state, state->substate_id)) {
		continue;
		}

		if ((cyc < 0) \|\|
		(cyc >= (min_residency_cyc + exit_latency_cyc))) {
		return state;
		}
		out_state = state;
		}

		return NULL;
		return out_state;
		}

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