Validation of Graphics System Features Using Media Workloads

Abstract

Graphics System Features are global functionalities that are applicable across each and every media unit. Every media test uses an outer cache - either L3 or external LLC (Last Level Cache). So, the outer cache is a global system feature. Yet, there is no universal way of accessing those outer caches and controlling their cacheability. My proposed solution is to use Memory Object Control State (MOCS) as a way of accessing the outer caches. A script needs to be developed which could resolve events that would eventually cause cache failures; like memory issues, invalid translations and cache misses. This script needs to be added and executed with a certain number of media tests to see if the intent is met.

The second scope of work is to enable preemption among media workloads. Traditionally, the graphics driver is used to enable preemption. This is done in the User mode, i.e. the calls (or preemption requests) made by the application have to go through several layers of hardware abstraction (OS, Kernel) to reach the hardware and get the task done. This means a time delay between when the request for preemption is issued and when it is serviced/executed. There are many overhead challenges. My proposed way is to use the graphics microcontroller (GuC) itself for scheduling and preemption of media workloads. This microcontroller is present on the Graphics Processing Engine (GPE) and any task run by it would talk directly to the hardware, and finish sooner. There is also a huge plus of using the microcontroller when it came to power savings - it could run independently in low power mode; even when the main core was in OFF state. Additionally, it has the authority to schedule workload on graphics sub-systems directly, without Host intervention. GuC is also a global system feature.