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Memory Optimization (Experimental)

Uddin-Lang provides experimental memory layout optimizations to improve performance in memory-constrained environments and sequential processing workloads.

Overview​

The memory optimization feature (--memory-optimize or -m flag) enables several experimental optimizations designed to reduce memory overhead and improve cache performance.

Usage​

CLI Usage​

# Enable memory optimization
./uddinlang --memory-optimize script.din
./uddinlang -m script.din

# Combine with profiling to measure optimization effects
./uddinlang --memory-optimize --profile script.din

Programmatic Usage​

// In Go code
options := interpreter.RunProgramOptions{
    MemoryOptimize: true,
}
result := interpreter.RunProgramWithOptions(program, options)

Optimization Features​

When memory optimization is enabled, the following optimizations are activated:

1. Tagged Value Types​

  • Reduces memory overhead by using tagged unions for value representation
  • Optimizes storage for different data types (integers, strings, booleans, etc.)
  • Improves memory locality and reduces allocation overhead

2. Compact Environment Structures​

  • Uses more memory-efficient data structures for variable storage
  • Reduces pointer indirection and memory fragmentation
  • Optimizes scope chain traversal

3. Cache-Friendly Data Layouts​

  • Reorganizes internal data structures for better CPU cache utilization
  • Improves sequential access patterns
  • Reduces cache misses during execution

4. Variable Lookup Caching​

  • Caches frequently accessed variable lookups
  • Reduces repeated scope chain traversals
  • Improves performance for variable-heavy code

5. Expression Memoization​

  • Caches results of expensive expression evaluations
  • Automatically detects and memoizes pure expressions
  • Reduces redundant computations

Performance Benefits​

Memory optimization can provide significant benefits in specific scenarios:

  • Memory Usage: 15-30% reduction in memory consumption
  • Cache Performance: Improved CPU cache hit rates
  • Sequential Processing: Better performance for non-concurrent workloads
  • Large Data Sets: More efficient handling of large arrays and objects

Compatibility and Limitations​

⚠️ Important Limitations​

  1. Concurrent Functions Incompatibility

    • Memory optimization is NOT compatible with concurrent functions
    • Cannot be used with: concurrent_map, concurrent_filter, concurrent_reduce
    • Attempting to use both will result in undefined behavior

  2. Thread Safety

    • Some optimization components are not thread-safe
    • Should not be used in multi-threaded environments
    • Memoization cache is particularly sensitive to concurrent access

  3. Experimental Status

    • This feature is experimental and may have stability issues
    • Not recommended for production systems requiring high reliability
    • API and behavior may change in future versions

When to Use Memory Optimization​

✅ Recommended for:

  • Sequential processing workloads
  • Memory-constrained environments
  • Performance-critical applications without concurrency
  • Batch processing scripts
  • Single-threaded data processing

❌ Avoid when:

  • Using concurrent functions
  • Multi-threaded environments
  • Production systems requiring maximum stability
  • Applications with unpredictable concurrency patterns

Examples​

Basic Usage​

# Run a sequential processing script with memory optimization
./uddinlang -m examples/data-processing.din

Performance Comparison​

# Without optimization
./uddinlang --profile script.din

# With optimization
./uddinlang --memory-optimize --profile script.din

Incompatible Usage (Avoid)​

# This will cause issues with memory optimization
data = [1, 2, 3, 4, 5]
result = concurrent_map(data, func(x) { return x * 2 })

Monitoring and Debugging​

Performance Profiling​

Use the --profile flag alongside --memory-optimize to measure optimization effects:

./uddinlang --memory-optimize --profile script.din

This will show:

  • Execution time improvements
  • Memory allocation statistics
  • Cache hit rates (when available)
  • Operation throughput

Debug Information​

For development and debugging, you can enable verbose output to see optimization decisions:

# Enable debug output (if available)
UDDIN_DEBUG=memory ./uddinlang -m script.din

Implementation Details​

The memory optimization system consists of several components:

  1. MemoryLayoutConfig: Configuration for experimental memory optimizations
  2. TaggedValue: Optimized value representation using tagged unions
  3. CompactEnvironment: Memory-efficient variable storage
  4. ExpressionOptimizer: Expression caching and optimization
  5. MemoryLayoutOptimizer: Coordination of all optimization components

Future Improvements​

Planned enhancements for memory optimization:

  • Thread-safe memoization for concurrent compatibility
  • Adaptive optimization based on workload patterns
  • More granular optimization controls
  • Better integration with garbage collection
  • Performance monitoring and auto-tuning

Troubleshooting​

Common Issues​

  1. Concurrent Function Errors

    • Problem: Using concurrent functions with memory optimization
    • Solution: Remove --memory-optimize flag or avoid concurrent functions

  2. Unexpected Performance Degradation

    • Problem: Optimization overhead exceeds benefits
    • Solution: Profile both optimized and non-optimized versions

  3. Memory Leaks

    • Problem: Memoization cache growing indefinitely
    • Solution: Restart the interpreter periodically for long-running scripts

Getting Help​

If you encounter issues with memory optimization:

  1. Check compatibility with your code patterns
  2. Compare performance with and without optimization
  3. Report issues on our GitHub repository
  4. Include profiling output and system information

Memory optimization is an experimental feature. Use with caution in production environments and always test thoroughly before deployment.