Zephyr Power & Performance
Maximize the efficiency of your embedded system by balancing power consumption and computational performance.
Core Workflows
1. Power Management (PM)
Implement system-level and peripheral-specific power saving strategies.
- Reference: power_management.md
- Key Tools:
pm_device_action_run,pm_state_set, Residency hooks.
2. Performance Tuning
Optimize critical code paths and monitor system resources.
- Reference: performance_tuning.md
- Key Tools:
CONFIG_THREAD_ANALYZER, Linker Map, Code relocation.
3. Memory Optimization
Relocate code and data to utilize the fastest memory available.
- Reference: performance_tuning.md
- Key Tools:
__ramfunc, Relocation scripts.
Quick Start (Device Suspend)
#include <zephyr/pm/device.h>
const struct device *spi0 = DEVICE_DT_GET(DT_NODELABEL(spi0));
void sleep_spi(void) {
pm_device_action_run(spi0, PM_DEVICE_ACTION_SUSPEND);
}
Professional Patterns (Optimization)
- Aggressive Suspend: Transition peripherals to low-power states as soon as their transaction is complete.
- ITCM/DTCM: Use Tightly Coupled Memory for time-critical control loops to avoid Flash latency.
- Runtime Monitoring: Always enable the thread analyzer during development to find the "RAM floor" for your application.
- Coordinated Sleep: To coordinate sleep across modules, see kernel-services for Zbus-based event-driven power management.
Automation Tools
- power_budget_estimator.py: Estimate average current and battery life from duty-cycle state data.
Examples & Templates
- power_budget_template.csv: Starter power-state budget sheet for battery-life estimation.
Validation Checklist
- Target peripherals enter and exit suspend/resume states without functional regressions.
- Measured idle and active power align with expected optimization deltas.
- Thread analyzer and map data confirm stack/RAM budgets are within limits.
- Relocated time-critical functions execute from intended memory region.
Resources
- References:
power_management.md: System states, device PM, and hooks.performance_tuning.md: Optimization strategies and relocation.
- Scripts:
power_budget_estimator.py: Duty-cycle based battery-life estimator.
- Assets:
power_budget_template.csv: Initial state/current budget template.
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