  This paper proposes a Priority-driven Accelerator Access Management (PAAM)
framework for multi-process robotic applications built on top of the Robot
Operating System (ROS) 2 middleware platform. The framework addresses the issue
of predictable execution of time- and safety-critical callback chains that
require hardware accelerators such as GPUs and TPUs. PAAM provides a standalone
ROS executor that acts as an accelerator resource server, arbitrating
accelerator access requests from all other callbacks at the application layer.
This approach enables coordinated and priority-driven accelerator access
management in multi-process robotic systems. The framework design is directly
applicable to all types of accelerators and enables granular control over how
specific chains access accelerators, making it possible to achieve predictable
real-time support for accelerators used by safety-critical callback chains
without making changes to underlying accelerator device drivers. The paper
shows that PAAM also offers a theoretical analysis that can upper bound the
worst-case response time of safety-critical callback chains that necessitate
accelerator access. This paper also demonstrates that complex robotic systems
with extensive accelerator usage that are integrated with PAAM may achieve up
to a 91\% reduction in end-to-end response time of their critical callback
chains.
