Jiffies Less System

The current tick based approach for all timing related activities in the linux kernel has some major drawbacks for two classes of linux systems. These are systems with virual processors and embedded systems with low power requirements. Both types of system suffer from the unnecessary ticks while the system is idle. Systems with virtual processors have a second problem area, the process time accounting based on timer ticks. A virtual processor only spents part of its processing power for a particular system image but each timer interrupt will account a full tick. In order to solve these two problem areas, a completly new timer infrastructure is needed - one that doesn't use the concept of a jiffies. For a jiffies less system the architectural backends needs callable common code functions for the different aspects of time, e.g. a function to update the wall time, a function to account virtual processor time to a process, a function to find the next timer event, etc. The backend chooses how it wants to implement its timers, for most architectures this will be the traditional jiffies approach - but hidden in the architecture files and not hardcoded in the common code.

The goal of this BOFS is to discuss this project with experts for other architectures.