Event Loop

The event loop drives all asynchronous behavior.

Loop Modes in Palfrey

• auto: uses uvloop if available, else asyncio default
• asyncio: explicit default asyncio behavior
• uvloop: explicit uvloop behavior
• none: do not alter loop configuration

How to choose

For most teams

Use --loop auto.

For strict reproducibility

Use explicit loop mode in production runbooks (asyncio or uvloop).

For debugging platform issues

Use --loop asyncio to eliminate loop implementation variability.

Verification checklist

• benchmark your own payloads and concurrency
• validate behavior on each target OS
• capture loop mode in incident reports

Performance considerations

Loop choice can change:

• tail latency behavior
• CPU efficiency under concurrent I/O
• behavior of some third-party async libraries

Plain-language explanation

Think of the loop as an air traffic controller for async operations. Different controllers can improve throughput and smoothness under load.