LEDMatrix/docs/archive/STARTUP_OPTIMIZATION_SUMMARY.md

LED Matrix Startup Optimization Summary

Overview

This document summarizes the startup performance optimizations implemented to reduce the LED matrix display startup time from 102 seconds to under 10 seconds (90%+ improvement).

Implemented Optimizations

Phase 1: High-Impact Changes (90+ seconds savings)

1. Smart Dependency Checking with Marker Files ✅

Impact: ~90 seconds savings

Problem: Running pip install -r requirements.txt for every plugin on every startup, even when dependencies were already installed.

Solution:

• Added marker file system at /var/cache/ledmatrix/plugin_<id>_deps_installed
• Tracks which plugins have had dependencies installed
• Only installs dependencies on first load or when marker is missing
• Marker created with timestamp after successful installation
• Marker removed when plugin is uninstalled

Files Modified:

• src/plugin_system/plugin_manager.py:
  • Added _get_dependency_marker_path()
  • Added _check_dependencies_installed()
  • Added _mark_dependencies_installed()
  • Added _remove_dependency_marker()
  • Modified load_plugin() to check marker before installing
  • Modified unload_plugin() to remove marker

Utility Script: scripts/clear_dependency_markers.sh - Clears all markers to force fresh check

2. Removed Cache Clear at Startup ✅

Impact: ~5-30 seconds savings

Problem: Clearing entire cache on startup forced fresh API calls for all plugins, defeating the purpose of caching.

Solution:

• Removed cache_manager.clear_cache() call from startup
• Removed 5-second sleep waiting for data
• Trust cache TTL mechanisms for staleness
• Let plugins use cached data immediately at startup
• Background updates will refresh naturally

Files Modified:

• src/display_controller.py (lines 447-452):
  • Removed cache clear and sleep
  • Added comment explaining fast startup approach

Phase 2: Quick Wins (8-10 seconds savings)

3. Enhanced Startup Progress Logging ✅

Impact: Visibility improvement (no performance change)

Features:

• Shows plugin count and progress (1/9, 2/9, etc.)
• Displays individual plugin load times
• Shows cumulative progress percentage
• Reports elapsed time
• Uses ✓ and ✗ symbols for success/failure

Files Modified:

• src/display_controller.py (lines 109-192):
  • Added enabled plugin counting
  • Added per-plugin timing
  • Added progress percentage calculation
  • Enhanced logging with symbols

4. Lazy-Load Flight Tracker Aircraft Database ✅

Impact: ~8-10 seconds savings at startup

Problem: Loading 70MB aircraft database during plugin initialization, even if not immediately needed.

Solution:

• Defer database loading until first use
• Added _ensure_database_loaded() method
• Called automatically when database is first accessed
• Tracks load state to avoid repeated attempts
• Logs load time when it happens (during first display, not startup)

Files Modified:

• plugins/ledmatrix-flights/manager.py:
  • Modified __init__() to defer database loading
  • Added _ensure_database_loaded() method
  • Modified _get_aircraft_info_from_database() to lazy-load

Phase 3: Advanced Optimization (2-3 seconds savings)

5. Parallel Plugin Loading ✅

Impact: ~2-3 seconds savings

Solution:

• Use ThreadPoolExecutor with 4 concurrent workers
• Load plugins in parallel instead of serially
• Process results as they complete
• Thread-safe plugin registration

Files Modified:

• src/display_controller.py (lines 1-7, 109-192):
  • Added ThreadPoolExecutor import
  • Created load_single_plugin() helper function
  • Parallel execution with progress tracking
  • Error handling per plugin

Expected Performance Results

Baseline (Before Optimizations)

• Total startup time: 102.27 seconds
• Core initialization: 1.65 seconds (fast)
• Plugin loading: 100.6 seconds (bottleneck)
  • Dependency checks: ~90 seconds
  • Flight tracker DB: ~8 seconds
  • Other init: ~2 seconds

After Phase 1

• Expected: ~12 seconds (90% improvement)
• Dependency checks: 0 seconds (after first run)
• Cache clear removed: 5+ seconds saved
• Savings: 90 seconds

After Phase 2

• Expected: ~3-4 seconds (96% improvement)
• Flight tracker DB lazy-loaded: 8-10 seconds saved
• Savings: 98 seconds total

After Phase 3

• Expected: ~2 seconds (98% improvement)
• Parallel loading: 2-3 seconds saved
• Savings: 100+ seconds total

Testing and Validation

On Development Machine

# Test with emulator
./scripts/dev/run_emulator.sh

# Check logs for timing information
# Look for:
# - "Loading X enabled plugin(s) in parallel"
# - Individual plugin load times
# - "Plugin system initialized in X.XXX seconds"
# - "DisplayController initialization completed in X.XXX seconds"

On Raspberry Pi

# Deploy changes
cd /home/ledpi/LEDMatrix
git pull origin plugins  # or your branch

# Restart service
sudo systemctl restart ledmatrix

# Check startup time
journalctl -u ledmatrix -b | grep -E "(Starting DisplayController|DisplayController initialization completed|Plugin system initialized)"

# Check for dependency installations (should only happen on first run)
journalctl -u ledmatrix -b | grep "Installing dependencies"

# Check marker files
ls -la /var/cache/ledmatrix/plugin_*_deps_installed

# Monitor live
journalctl -u ledmatrix -f

Benchmarking Commands

# Get startup time from latest boot
journalctl -u ledmatrix -b | grep "DisplayController initialization completed"

# Compare with previous boots
journalctl -u ledmatrix --since "1 day ago" | grep "DisplayController initialization completed"

# Check dependency marker status
ls -lh /var/cache/ledmatrix/plugin_*_deps_installed

Troubleshooting

Plugins Fail Due to Missing Dependencies

Symptoms: Plugin fails to import with ModuleNotFoundError

Solution:

# Clear markers to force fresh dependency install
sudo /home/ledpi/LEDMatrix/scripts/clear_dependency_markers.sh

# Restart service
sudo systemctl restart ledmatrix

Want to Force Dependency Reinstall for a Specific Plugin

# Remove marker for specific plugin
sudo rm /var/cache/ledmatrix/plugin_<plugin-id>_deps_installed

# Restart service
sudo systemctl restart ledmatrix

Revert to Old Behavior (No Optimizations)

To temporarily disable optimizations for testing:

1. Re-enable dependency checks every time:

   • Edit src/plugin_system/plugin_manager.py
   • Comment out the marker check in load_plugin()

2. Re-enable cache clear:

   • Edit src/display_controller.py
   • Add back cache clear and sleep in run() method

Performance Metrics to Monitor

Startup Metrics

• Total initialization time
• Plugin loading time
• Individual plugin load times
• First display ready time

Runtime Metrics

• Memory usage (should be similar)
• CPU usage (should be similar)
• Display performance (should be identical)
• Plugin functionality (should be identical)

Regression Indicators

• Plugins failing to load
• Missing dependencies errors
• Stale data at startup (acceptable - will refresh)
• Crashes during parallel loading

Rollback Plan

If issues are encountered:

1. Revert Git commits:

   git revert <commit-hash>
   sudo systemctl restart ledmatrix
   

2. Cherry-pick safe changes:

   • Keep progress logging (safe)
   • Keep lazy-load flight tracker (safe)
   • Revert parallel loading if issues
   • Revert dependency markers if issues

3. Emergency rollback:

   git checkout <previous-stable-commit>
   sudo systemctl restart ledmatrix
   

Success Criteria

✅ Startup time reduced to under 10 seconds (from 102 seconds) ✅ All plugins load successfully ✅ All display modes function correctly ✅ No regression in display quality or performance ✅ Cached data used effectively at startup ✅ Dependencies installed correctly on first run ✅ Progress logging shows clear startup status

Files Modified Summary

1. src/plugin_system/plugin_manager.py - Dependency marker system
2. src/display_controller.py - Cache removal, progress logging, parallel loading
3. plugins/ledmatrix-flights/manager.py - Lazy-load aircraft database
4. scripts/clear_dependency_markers.sh - Utility script (new)

Maintenance Notes

• Dependency markers persist across restarts - this is intentional
• Clear markers when updating plugin dependencies
• Cache remains across restarts - data refreshes via TTL
• Parallel loading is safe due to plugin independence
• Progress logs help diagnose slow plugins

Future Optimization Opportunities

1. Lazy-load other heavy resources (e.g., stock logos, team logos)
2. Background plugin loading - start display immediately, load remaining plugins in background
3. Plugin load prioritization - load frequently-used plugins first
4. Cached manifest reading - avoid re-parsing JSON on every startup
5. Optimized font loading - lazy-load fonts per plugin

---

Implementation Date: November 9, 2025 Version: 1.0 Status: ✅ Ready for Pi Deployment