Optimize WASM frontend performance · Issue #39 · eddmann/phpboy · GitHub
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Optimize WASM frontend performance #39

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Optimize WASM frontend performance#39

Description

@eddmann
eddmann
opened on Nov 10, 2025

Description

Review and optimize the WASM frontend to improve performance, reduce latency, and ensure smooth 60 FPS gameplay in the browser.

Tasks

  • Profile current WASM performance bottlenecks
  • Measure frame time and identify slowest components
  • Optimize PHP-WASM runtime configuration
  • Review JIT settings and PHP compilation flags
  • Optimize JavaScript-PHP interop layer
  • Reduce memory allocations and garbage collection
  • Optimize frame rendering pipeline
  • Implement WebGL rendering if beneficial
  • Add performance metrics/FPS counter
  • Test on various browsers and devices
  • Compare with other WASM emulators

Areas to Investigate

  • PHP-WASM JIT optimization settings
  • Memory management and object pooling
  • JavaScript rendering performance (Canvas 2D vs WebGL)
  • Input handling efficiency
  • Audio buffer management
  • File system operations (ROM loading, save states)

Acceptance Criteria

  • Maintains 60 FPS on modern browsers
  • Startup time is acceptable (<3 seconds)
  • Input latency is minimal
  • Works on mobile devices at reasonable speed
  • Memory usage is stable over time

Performance Targets

  • Frame time: <16.67ms (60 FPS)
  • Input latency: <50ms
  • ROM load time: <2s for typical ROMs
  • Memory usage: <100MB for typical games

References

  • Current bundler: bin/bundle-wasm.php
  • Web frontend: web/ directory

Activity

  1. eddmann commented on Nov 10, 2025

    @eddmann
    eddmann
    on Nov 10, 2025
    OwnerAuthor

    Current Implementation Status: ✅ Core Complete, 🔄 Performance Work Needed

    What's Already Implemented

    The WASM frontend is fully functional with these features:

    ✅ Complete WASM Bundler (bin/bundle-wasm.php)

    • Bundles all 69 PHP source files into single WASM-compatible file
    • PHP 8.2 compatibility transformations
    • Automatic namespace conversion

    ✅ Browser Frontend (web/)

    • Full HTML5 interface with Canvas 2D rendering (160x144)
    • FPS counter and performance monitoring built-in
    • Speed controls, pause/resume, savestate support
    • Screenshot capability
    • JavaScript-PHP bridge using php-wasm

    ✅ PHP-WASM Configuration

    • JIT enabled: opcache.jit=1255, opcache.jit_buffer_size=100M
    • Batch rendering: Processes 4 frames per render to reduce overhead
    • Non-blocking rendering loop

    Performance Status

    ⚠️ Known Performance Issues:

    • README notes: "WASM frontend has significant performance overhead"
    • Current rendering uses Canvas 2D only (not hardware-accelerated WebGL)
    • Struggles to maintain 60 FPS on most browsers

    Tasks Remaining

    High Priority:

    • Profile current WASM performance bottlenecks ✅ FPS counter implemented
    • Implement WebGL renderer (main performance win)
    • Optimize JavaScript-PHP interop layer
    • Add performance metrics dashboard (basic FPS exists)

    Medium Priority:

    • Test on various browsers and devices
    • Memory profiling and optimization
    • Compare with other WASM emulators

    Low Priority:

    • Optimize PHP-WASM JIT settings (already configured)
    • ROM load time optimization

    Next Steps

    1. WebGL Renderer: Moving from Canvas 2D to WebGL would provide hardware acceleration - this is likely the biggest performance win
    2. Profiling: Use browser DevTools to identify JavaScript/WASM bottlenecks
    3. Memory Management: Profile memory allocations during gameplay

    References

    • Bundler: bin/bundle-wasm.php
    • Web frontend: web/ directory
    • Current FPS counter: web/js/phpboy.js
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