performance
Performance Strategy
Optimization approaches and technical constraints for tile processing performance.
Performance Requirements
⚠️ NEEDS DISCUSSION: Specific performance targets and constraints have not been established yet.
General Goals:
- Support many active tiles simultaneously
- Performance should scale reasonably with world activity
Optimization Systems
Active Region System (NOT IMPLEMENTED)
⚠️ NOT IMPLEMENTED: Active region optimization was decided against - implementation deemed too complex for expected benefit. Team is planning for relatively few dormant areas instead.
Purpose: Avoid processing static regions to maintain performance.
~~Implementation:
- Divide world into 32×32 tile chunks (chosen to balance GPU workgroup efficiency with memory overhead)
- Track chunks with active tiles in GPU buffer
- Shaders only process listed active chunks
- Activity propagates to neighboring chunks automatically
- Dormant regions have minimal GPU cost~~
~~Benefits:
- Automatic scaling with activity level
- Efficient memory bandwidth usage
- Reduced compute shader dispatches~~
Texture-Based Storage
GPU Cache Optimization: Leverage 2D data access patterns for efficient memory reads
Bit-Packing: 32-bit tiles maximize cache line utilization
- Tile Type (~6 bits): 64 possible types per layer
- Velocity (16 bits): Movement vector for physics
- Custom Data (10 bits): Health, timers, charges, etc.
Ping-Ponging: Dual texture approach prevents read-after-write hazards
Chunk-Based Processing
GPU Workgroup Efficiency: 32×32 chunks align with GPU architecture
Memory Layout: Textures use r32uint format for optimal GPU cache performance
Parallel Processing: Each GPU thread handles one tile for maximum parallelization
⚠️ POTENTIAL OPTIMIZATIONS: Additional GPU techniques
- Memory Coalescing: Threads in a warp access consecutive memory addresses simultaneously for maximum bandwidth
Shader Design Principles
⚠️ GUIDELINE: Minimize divergent branching
- Structure algorithms so threads in the same warp follow similar execution paths
- When early exits are necessary, group similar work patterns together to reduce warp divergence
Technical Constraints
Hard Limits
Tile Types: ~64 per layer (chosen to be comfortably under realistic limits)
World Size: Fixed at initialization (no dynamic streaming)
Mana Types: 8 maximum (player state buffer constraint)
Spell Hand: Size TBD based on UI and gameplay needs
Performance Scaling
⚠️ NEEDS DISCUSSION: Specific performance characteristics to be determined through testing
- 32×32 chunks chosen to balance GPU workgroup efficiency with memory overhead
- GPU texture cache considerations
- Parallel processing efficiency targets
Offline Optimizations
Rule Compilation Approach
⚠️ SUGGESTION: Potential optimization techniques for rule compilation:
- Compile-time specialization for specific use cases
- Dead code elimination for unused rule paths
- Constant folding for pre-computed values
- Loop unrolling for neighbor checks
Build-Time Processing
Shader Generation: Move complex rule logic to build time
Asset Optimization: Texture and mesh preprocessing
⚠️ NEEDS DESIGN: Specific optimization pipeline implementation
Risk Management
Performance Monitoring
⚠️ SUGGESTION: Potential monitoring and validation approaches:
- Automated benchmarks to prevent regressions
- Frame timing and bottleneck profiling
- Determinism validation across runs
Bottleneck Identification
⚠️ Major Unsolved Issues:
- Frame rate coordination between different systems
- GPU thread execution order determinism
- Memory bandwidth optimization across modules
Monitoring and Debugging
Performance Profiling
⚠️ SUGGESTION: Potential profiling capabilities to develop:
- Frame timing monitoring for pipeline stages
- GPU utilization tracking
- Memory bandwidth analysis
- Active region processing visualization
Debug Capabilities
⚠️ SUGGESTION: Potential debugging tools:
- Tile inspector for real-time data examination
- Rule tracer for activation analysis
- Determinism validation tools