Fairness

[tanveergill]

Description of change

Checklist

• [ ] Tested in playground or other setup
• [ ] Screenshot (Grafana) from playground added to PR for 15+ minute run
• [ ] Documentation is changed or added
• [ ] Tests and/or benchmarks are included
• [ ] Breaking changes

Summary by CodeRabbit

• New Features

  • Introduced fairness_label_key for enforcing fairness in workload scheduling.
  • Added new fairness-related metrics for observability.

• Documentation

  • Updated configuration specification with fairness_label_key details.
  • Revised observability documentation to reflect new metrics.

• Refactor

  • Enhanced the Scheduler interface with additional workload identification.
  • Updated scheduling logic to incorporate fairness in request handling.

• Chores

  • Adjusted pre-commit spell check configuration.

• Bug Fixes

  • Removed obsolete metrics related to previous scheduling mechanisms.

[coderabbitai[bot]]

Walkthrough

The system's scheduling logic has been updated to introduce a new fairness mechanism that differentiates requests based on a fairness_label_key. This ensures a more equitable distribution of resources among requests within the same priority. Metrics related to the previous Weighted Fair Queuing Scheduler have been removed in favor of new ones that track this fairness. Additionally, the scheduler code now includes methods for identifying request workload and flow, and the configuration files have been adjusted to reflect these changes.

Changes

File Path	Change Summary
api/aperture/policy/language/v1/flowcontrol.proto, docs/content/reference/configuration/spec.md	Added fairness_label_key to enforce fairness in request scheduling.
docs/content/reference/observability/prometheus-metrics/agent.md	Removed WFQScheduler metrics; added workload fairness metrics.
pkg/scheduler/scheduler.go, pkg/scheduler/wfq.go, pkg/scheduler/.../scheduler.go	Updated Scheduler interface and WFQScheduler with new methods and fields for fairness; metrics adjusted accordingly.
pkg/scheduler/wfq_test.go, pkg/metrics/schema.go	Updated tests and metrics schema to align with scheduling fairness changes.
pkg/policies/flowcontrol/actuators/workload-scheduler/scheduler.go	Modified Factory struct, SchedulerMetrics, and Decide method to accommodate fairness metrics.
.pre-commit-config.yaml	Updated codespell configuration.

"In the burrow of the code, a change was sown,
🐇 A fairness key in the scheduler's home.
No more FIFO, just fair play,
For every request that hops its way."

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