Logging

Logging has been refactored to improve clarity, reduce noise, and clearly separate user-facing signals from system internals.

Key Improvements

• Clear separation of logs

  • Monarch system logs and user logs are cleanly separated.
  • User-visible faults are communicated only via exceptions and supervision events.

• Improved error clarity

  • Errors are categorized (e.g., user, system, infrastructure).
  • Actor names are reported in user-understandable syntax.
  • Actor failure reports include richer context and causal chaining.

• Structured logging

  • Errors emit structured log records suitable for filtering and aggregation.
  • Supervision events follow a defined schema.

• Reduced default noise

  • Log forwarding, aggregation, and enrichment are disabled by default.
  • Log messages have been audited for signal quality.

Observability

Observability has been expanded across actors, meshes, and endpoints.

Key Improvements

• Comprehensive metrics

  • Endpoint latency, throughput, payload size, and error counts are universally available.
  • Metrics are collected on both client and server sides.

• Lifecycle instrumentation

  • Actor, process, and mesh state changes emit structured events.
  • Supervision events are fully instrumented.

• Root-cause visibility

  • The first triggering event in a failure cascade is surfaced.
  • User-parseable actor IDs are linked to internal actor identifiers.

• Tracing

  • Distributed spans cover message send and receive paths.
  • Traces can be visualized via Perfetto and standard tracing backends.

• Performance awareness

  • Instrumentation overhead has been reduced and made configurable.

Build Hygiene & Compatibility

Build and dependency management has been simplified.

Key Improvements

• RDMA and tensor engine support are dynamically loaded. The same wheel can be installed
• Monarch no longer has a binary dependency on PyTorch.
  • PyTorch is required only at the Python layer.
  • Startup time and binary size are significantly reduced.

Networking

Networking reliability has improved, with a focus on Lightning integration.

Key Improvements

• Lightning integration works on HostMesh v1.
• Networking behavior is documented and standardized for OSS usage.

Deprecation

Legacy v0 codepath has been removed