Investigate QUIC upload performance gap - achieving only 8Mbps vs 100-500Mbps potential

Problem

Deploy asset uploads are currently achieving only 8Mbps or less throughput to eu1.miren.dev, which is significantly below the network's demonstrated capability.

Network Baseline Testing Results

Recent iperf3 UDP performance testing between local environment and eu1.miren.dev shows:

• Network RTT: ~124ms (expected for transatlantic)
• UDP throughput capabilities:
  • ✅ 100 Mbps: 0% packet loss, stable performance
  • ✅ 500 Mbps: 0% packet loss, excellent stability
  • ⚠️ 1 Gbps: 4.88% packet loss (network capacity limit)
• Parallel streams: 4 concurrent streams handle 400 Mbps aggregate with 0% loss
• Jitter: <0.5ms (excellent for QUIC pacing)

Performance Gap

• Current: 8 Mbps upload speeds during deploys
• Potential: 100-500 Mbps based on UDP testing
• Gap: 12-60x performance improvement possible

Investigation Areas

1. QUIC Configuration
   • Initial congestion window settings
   • Bandwidth estimation parameters
   • Pacing and flow control settings
   • Stream multiplexing configuration
2. Application Layer
   • Asset chunking size
   • Concurrent upload streams
   • Client-side throttling or buffering
3. Server-side Processing
   • Receiver buffer sizes
   • Processing bottlenecks during asset ingestion
   • Disk I/O constraints
4. Network Path
   • MTU discovery issues
   • Middlebox interference with QUIC
   • Asymmetric routing effects

Acceptance Criteria

• Identify root cause(s) of throughput limitation
• Document QUIC configuration parameters currently in use
• Implement fixes to achieve at least 100 Mbps upload speeds
• Verify improvements with production deploy tests

Testing Notes

All iperf3 test data available showing baseline UDP performance characteristics. The network path supports high-bandwidth UDP traffic with minimal loss up to 500 Mbps.