Troubleshooting Performance & Bottlenecks

RUSEON Core is engineered for high-concurrency video streaming with sub-millisecond playlist delivery and zero-copy frame routing. If you observe elevated CPU usage, memory growth, or frame drops, use this guide to identify and resolve the root bottleneck.

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1. High CPU Utilization

Under normal operation, RUSEON Core consumes negligible CPU because it transmuxes rather than transcodes.

Remediation Steps:

1. Disable Debug Logging: Running in debug mode (server.debug: true) incurs additional logging overhead. Ensure server.debug: false in production.
2. Inspect pprof CPU Profile: If server.pprof_port: 6060 is enabled:

   go tool pprof -top http://localhost:6060/debug/pprof/profile?seconds=30

3. Inspect Real-Time Memory Visualizer (Statsviz): Navigate to http://localhost:8080/debug/statsviz/ in your browser for live Goroutine, Heap, and GC allocation graphs.

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2. Memory Growth & Garbage Collection Tuning

If RAM usage climbs unexpectedly:

1. Configure GC Tuning in config.yaml: RUSEON Core provides built-in Go runtime memory limits:

   server:
     gc_percent: 50              # Default GOGC target
     gc_memory_limit_mb: 2048    # GOMEMLIMIT soft ceiling

2. Page Cache vs Process Memory: Distinguish between RUSEON's RSS memory and the Linux kernel Page Cache:

   # Check actual process RSS memory
   ps -aux | grep ruseon
   
   # Check Linux Page Cache vs Free RAM
   free -h

   RUSEON automatically invokes POSIX_FADV_DONTNEED to prevent Page Cache thrashing.

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3. Buffer Drops & Slow Consumer Saturation

If ruseon_ringbuffer_drops_total is increasing in Prometheus:

• Root Cause: An outbound subscriber channel (a slow WebRTC client or high-latency disk write) is not draining frames fast enough.
• Protection: The RingBuffer drops non-keyframe P-frames for that specific subscriber and sets the NeedsIFrame flag to preserve global server stability.
• Remediation: Check network bandwidth between RUSEON and client players, or optimize disk write throughput.

Related Documentation

• Troubleshooting Overview
• Page Cache Thrashing Deep Dive
• Performance Benchmarks
• Runtime Profiling with pprof