Automotive Whitepapers

From Xen
Revision as of 18:14, 19 February 2018 by Rpersaud (talk | contribs)
In the following article I want to describe GlobalLogic’s team experience of bring-up a driver domain on ARM platform. The results that we have achieved with a driver domain were introduced at CES 2015 show and GENIVI event.
The paper analyzes the latency of OS scheduling for symmetric and asymmetric multi-processing support cases – as well as incoming packet handling in Xen – using default credit and real-time schedulers. It also demonstrates how the real-time scheduler affects latency. With RT-Xen support, most of the incoming packets are predictably handled within 1 millisecond with a small overhead at the destined guest OS, which is a feasible time bound for most soft real-time applications.
As we all know, one of the most common sources of OS crashes are hardware drivers and the issues with them. On systems with visualization, it seems logical to create a separate domain and place hardware drivers (or at least the buggiest of them) there. One of the most significant tasks of creating a system with such a driver domain is to correctly provide it with resources (e.g., IO memory, IRQs). The main idea of passthrough described in the paper is to grant access for DomD through Dom0.
As modern ARM SoCs become faster and faster, they are now capable of performing the same high­load tasks that desktop PCs were performing a few years ago, such as HD video playback and high­speed graphic rendering. The structure of an ARM SoC is also now quite complicated. In addition to containing a CPU module or modules, it also includes several peripheral modules (e.g., UARTs, Wireless, HDMI ports, etc.) and co­processors that are designed to help with high­load tasks like Graphic Processor Unit (GPU) or Video Processor Unit (VPU) are assembled together with the main CPU on almost all modern ARM SoCs that are designed for mobile and automotive markets. The article will cover few aspects of sharing such coprocessors when running Xen on embedded SoC.