Explore a groundbreaking system for performance-aware routing that adapts to traffic changes at hardware speeds in this 20-minute conference talk from NSDI '20. Dive into Contra, a versatile solution that operates seamlessly across various network topologies and routing policies. Learn how users can write network-wide policies to rank paths based on current performance, and discover the innovative compiler that transforms these policies into switch-local P4 programs. Understand the specialized distance-vector protocol that generates compact probes for dynamic path optimization. Examine Contra's scalability in large networks and its competitive performance in flow completion times compared to topology-specific systems. Gain insights into the Contra language syntax, policy analysis, handling of changing metrics, and evaluation results across different network scenarios.