2012 Embedded Linux Conference | Presentations

Comparing Power Saving Techniques for Multicore ARM Platforms

CPU hotplug is used on ARM platform as a power management feature for aggressive low power use cases. It has not been initially designed for that purpose, which implies some constraints on its use but the same power consumption level can't be reached with the scheduler load balance and/or additional features like cpuset up to now. This presentation will discuss how CPU hotplug matches the low power use case requirements and how we can get closer to this behavior with sched_mc. Then we will also show what prevents the scheduler to reach the same power consumption level as CPU hotplug and how we can solve some of these issues. This presentation is aimed at anybody who is interested to understand why ARM platforms still use CPU hotplug and what should be done to replace CPU hotplug by a load balance decision

Vincent Guittot, Linaro

Vincent has worked in the embedded software industry since 2000. He has developed drivers for various peripherals and coprocessor on ARM-based platforms. Since 2005, he has focused on mobile phone running Linux and more especially the power management.