Performance Overview

Understanding rninja's performance advantages.

Performance Comparison

Scenario	Ninja	rninja	Improvement
No-op build	0.23s	0.01s	23x
Cold build (100 files)	2.63s	1.79s	1.5x
Cached rebuild	2.63s	0.15s	17.5x
Warm incremental	-	2-5x	faster

Why rninja is Faster

Content-Addressed Caching

• Skip rebuilds when inputs unchanged
• Cache survives clean builds
• Branch switching reuses artifacts

Fast No-op Detection

• Optimized buildlog with pre-computed hashes
• MtimeCache avoids repeated stat() calls
• Parallel file checking with rayon

Modern Scheduler

• Tokio async runtime
• Pool-aware scheduling
• Better CPU utilization

Key Metrics

Metric	Target	Good
No-op build	< 50ms	< 100ms
Cache hit rate	> 80%	> 60%
Cache lookup	< 50ms	< 100ms

Next Steps

• Benchmarks - Detailed performance data
• Optimization - Tuning guide
• Profiling - Build analysis