Use Dmabuf to Streamline Sensor Data Handling - Wendy Liang, Cruise LLC

Use Dmabuf to Streamline Sensor Data Handling - Wendy Liang, Cruise LLC Modern automotive systems for self driving vehicles have many sensor, like cameras. These sensors generate a lot of data that needs to be processed by the SoC. In order to handle the sensor data efficiently it is necessary to avoid data copying as much as possible. Another factor that needs to taken into consideration is that different memories can have different access latencies for different device. In this presentation we will talk about the basics of dmabuf, dma fence, dma heap and reserved memory Linux kernel frameworks, and how they can be used to address the requirements of modern heterogeneous data processing pipelines. We will show how to use the dmabuf and reserved memory framework to allow applications to allocate buffers from preferred memory. Furthermore we will propose a solution for sharing buffers between different accelerators to setup a zero copying data pipeline. In addition, we will explore how to use dma fence for synchronization between devices without the intervention from userspace application, and how the userspace application can use dma fence to monitor the data execution on the path.