This contains two packages:

• simple_timer contains timing related functions, and a wrapper for calling some kernel scheduling functions
• priority_executor contains the modified executor and some nodes to test it

In priority_executor:

• priority_executor.cpp subclasses rclcpp::Executor to allow for additional customization
• priority_memory_strategy.hpp is a modified version of rclcpps allocator_memory_strategy.hpp that selects callbacks based on either the earliest deadline, or a relative priority. Executor polls this for ready callbacks.
• test_nodes.cpp adds timer-based publishing nodes and dummy worker nodes that can be arranged in chains. It uses dummy_workload.hpp to generate a workload.
• f1tenth_test.cpp sets up a chain of nodes similar to https://intra.ece.ucr.edu/~hyoseung/pdf/rtas21_picas.pdf
• test_publisher.cpp creates two small chains on a single executor to demonstrate an overloaded executor.
• usage_example.cpp shows how to set deadlines for callbacks and timers