LinuxCon Europe + CloudOpen Europe

Linux must operate in a world of limited power budgets. Hand-held devices must simultaneously be responsive, cool,light, and deliver long battery life. Embedded systems must be silent. Servers must maximize compute efficiency while obeying site-wide power limits. Linux infrastructure for responding to power and thermal limits is rooted in a history of these being exceptional events. How will Linux handle a future where power and thermal limits are reached in normal operation? Here we summarize the techniques available to Linux to respond to power and thermal limits, contrasting their effectiveness. We detail power-clamp, a new technique to manage power through idle injection. We show how power-clamp can provide high efficiency operation as compared to previous power capping techniques.