What problem does it solve?
Training large JAX models often suffers from slow startup, long compilation, or poor throughput, and raw profiler output is hard to interpret. This Skill ingests XPlane protobufs and Perfetto traces from Levanter profiler directories and turns them into structured summaries, root-cause reports, and before/after comparisons.
Core Features & Use Cases
- Profile Capture Guidance: Configure Levanter profiler flags, JAX profile options, and XLA flags so traces retain named-scope regions and HLO metadata.
- Structured Summaries: Parse XPlane protobufs (with optional xprof aggregate tables) into JSON summaries exposing top ops, pre-op gaps, collective breakdowns, and bottleneck statements.
- Optimization Workflow: Measure, patch, re-measure, then compare runs with provenance checks, regression tracking history, and publish reports back to W&B.
- Use Case: A run shows a large idle gap before the loss backward kernel; query the summary for gap attribution, apply a bounded fix, and use the compare command to verify the step-time improvement.
Quick Start
Ask the assistant to summarize the profiler output for a given W&B run id and report the top ops by exclusive time and any pre-op gaps.