How do you integrate DVFS with other hardware and software techniques for energy management?

1 Hardware monitoring

To apply DVFS effectively, you need to monitor the activity, power, and temperature of the hardware components. Hardware monitoring can be done by using sensors, counters, or models that estimate the power and thermal behavior of the system. Hardware monitoring can provide feedback to the DVFS controller, which can adjust the voltage and frequency levels dynamically or based on predefined policies. Hardware monitoring can also enable adaptive and predictive DVFS strategies, which can anticipate the workload variations and optimize the energy efficiency.

2 Software scheduling

Software scheduling is a software technique that coordinates the execution of tasks and threads on the available hardware resources. Software scheduling can influence the DVFS decisions by allocating tasks to different cores, clusters, or domains, and by balancing the load and performance among them. Software scheduling can also exploit the heterogeneity of the hardware, which may have different voltage and frequency ranges or capabilities. Software scheduling can communicate with the DVFS controller through interfaces or hints, and can use information from the hardware monitoring to optimize the energy management.

3 Power gating

Power gating is a hardware technique that switches off the power supply to idle or unused parts of the system, such as cores, caches, or peripherals. Power gating can complement DVFS by reducing the static power consumption, which is independent of the voltage and frequency levels. However, power gating also has some drawbacks, such as the latency and energy overhead of turning on and off the components, and the possible loss of state and data. Therefore, power gating requires careful coordination with the DVFS controller and the software scheduler, which can determine when and how to use power gating based on the workload and performance requirements.

4 Thermal management

Thermal management is a hardware and software technique that controls the temperature of the system and prevents overheating or thermal throttling. Thermal management can affect the DVFS decisions by imposing constraints or limits on the voltage and frequency levels, or by triggering emergency actions such as frequency scaling or shutdown. Thermal management can also benefit from the DVFS decisions by reducing the heat generation and dissipation of the system. Thermal management can use hardware monitoring to measure the temperature of the components, and software scheduling to distribute the heat among them. Thermal management can also use other techniques such as cooling, fan control, or thermal-aware placement to enhance the energy efficiency.

5 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?