TASK-400: HDR Histogram Integration #73
Description
Description
Integrate HDR Histogram for latency metrics per METRICS.md
Phase
Set up development infrastructure with Tiger Style discipline
Test-First Requirements
⚠️ Write tests BEFORE implementation
- Test histogram accuracy (known inputs)
- Test percentile calculations
- Test memory bounds
Acceptance Criteria
- Vendor HDR Histogram C library
- Zig bindings for HDR Histogram
- Configuration: 1ns to 1 hour, 3 significant figures
- Record latencies from event log
- Compute percentiles: p50, p90, p95, p99, p999
- Bounded memory usage (independent of sample count)
- Minimum 2 assertions per function
- >90% test coverage
- Accuracy verified against known distributions
- All tests pass
Dependencies
- TASK-100
Files to Create/Modify
vendor/hdrhistogram/...
src/hdr_histogram.zig
tests/unit/hdr_test.zig
Estimated Effort
16 hours
Tiger Style Requirements:
- Minimum 2 assertions per function
- All loops are bounded
- Explicit error handling (no silent failures)
- Code formatted with
zig fmt - Pre-commit hook passes
- All tests pass