# Code Review Issues - parser-benchmarks

## BLOCKING Issues

### 1. CV > 5% for all benchmarks (BLOCKING)

**Severity**: BLOCKING
**Location**: All three parser benchmarks
**Issue**: The acceptance criteria explicitly requires "CV < 5% for all benchmarks", but all three benchmarks fail to meet this requirement:

- `parser_simple`: CV = 18.37% (std_dev: 15.29ns / mean: 83.24ns)
- `parser_complex`: CV = 7.94% (std_dev: 19.37ns / mean: 243.99ns)
- `parser_variables`: CV = 19.09% (std_dev: 44.98ns / mean: 235.54ns)

**Root Cause**: The parser operations are too fast (80-250ns), resulting in high variance. At this timescale, CPU scheduling, cache effects, and other system noise dominate the measurement. The current configuration (1000 samples, 10s measurement time) is insufficient to achieve stable measurements for such fast operations.

**Impact**: The benchmarks do not meet the acceptance criteria and cannot be used for reliable performance tracking or regression detection.

**Recommendation**: To achieve CV < 5%, consider:
1. Increase `sample_size` from 1000 to 10000 or higher
2. Increase `measurement_time` from 10s to 30s or higher
3. Add warmup iterations to stabilize CPU frequency scaling
4. Parse larger/more complex inputs to increase operation time and reduce relative variance
5. Use `--warm-up-time` criterion parameter to allow CPU to stabilize

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## Summary

The implementation correctly:
- ✅ Created `benches/parser_benchmarks.rs` with three benchmarks
- ✅ Pre-tokenized input outside the benchmark loop to isolate parser performance
- ✅ Generated `estimates.json` files for all three benchmarks
- ✅ Updated `Cargo.toml` with the parser_benchmarks bench target
- ✅ Used appropriate test inputs matching the issue description

However, it fails a critical acceptance criterion:
- ❌ **CV < 5% for all benchmarks** - All three benchmarks have CV values between 7.94% and 19.09%

This is a **BLOCKING** issue that prevents approval. The benchmarks are functionally correct but do not meet the stability requirements specified in the acceptance criteria.
