dnsimple / erldns / 20720987691

85%

push

github

Implement CoDel queue management for UDP workers (#301)

* Implement CoDel queue management for UDP workers

Replace the previous UDP worker queue management with CoDel (Controlled
Delay) algorithm as specified in RFC 8289. CoDel provides better queue
management by controlling delay rather than queue length, resulting in
more responsive behaviour under load.

Changes:
- Add erldns_codel module implementing RFC 8289 CoDel algorithm
  - Support for configurable interval and target parameters
  - Proper handling of drop state transitions and control law
  - Hysteresis logic for re-entering drop state
- Update erldns_proto_udp to use CoDel for queue management
  - Initialise CoDel with ingress timeout as interval
  - Integrate CoDel dequeue decisions into packet processing
  - Implement drop loop for draining queue when dropping
- Add comprehensive test suite covering all CoDel code paths
  - Tests initialisation variants, state transitions, control law,
    hysteresis, and edge cases

The CoDel implementation uses the ingress_request_timeout as the
interval parameter, allowing per-listener configuration of the queue
management behaviour.

48 of 51 new or added lines in 3 files covered. (94.12%)

1472 of 1753 relevant lines covered (83.97%)

1169.58 hits per line