Jean Pihet

Kernel profiling tools status on ARM and ARM64: - perf status, - ARM and ARM64 support, - callchain unwinding mechanisms and support, - patches status: merged, pending, in development, - links to discussions (LKML) and patches.

The profiling tools in the kernel are changing at a fast pace. This talk is about the support for ARM and ARM64 architecture and the development of features for these architectures, namely the callchain unwinding. The presentation goes over: - the detailed description of the feature, - the methods used to do the callchain unwinding (fp, exidx, dwarf etc.), - the status of the on-going patches, - the remaining work to be done, - the links to patches, discussions on the mailing lists, - -if needed and if time allows- a demo of the feature.

Due to the nature of the new SoC architectures the Power Management needs a new model for the various system latencies. The talk presents: - the concepts of system, devices, wake-up and resume latencies, - the recent changes in the devices framework for the latency, why and how to make it generic, - the recent changes in the ARM/OMAP platform code for the system latency, - the problems encountered while modeling and measuring the various latencies, - a proposal on the model, - the planned changes in the device framework, the platform code and the APIs. This talk is oriented towards Linux power management developers and users. The generic model covers all flavors of Linux, from the embedded device up to the multi processor computing server.