# Performance: Benchmarks, Profiler, Optimizer, Memory & Concurrency
Comments indicating placeholders, mocks, or simplified logic and proposed real-world directions.
**Scope:** `src/performance/` (benchmark, profiler, optimizer, memory, concurrency), `benches/` (performance.rs, performance_benchmarks.rs), and main binary use of performance APIs.
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## Status
**Implemented:** Criterion-based benchmarks in `benches/performance.rs` (lexer, parser, runtime, stdlib, memory, concurrent access). Additional Criterion benchmarks in `benches/performance_benchmarks.rs` (lexer/parser/runtime by size, parameterized). In-library `BenchmarkRunner` / `LanguageBenchmarks` (lexer, parser, runtime suites), `Profiler` with scoped timing and report generation, `Optimizer` with strength reduction and constant folding, `MemoryManager` and `ConcurrencyProfiler`. Main binary uses performance module for `test_performance_optimization()` (benchmark runner, profiler, optimizer, memory, concurrency).
**Remaining:** Real memory usage APIs in benchmark/profiler; real loop optimizations in optimizer; runtime benchmark "function_calls" wired to real runtime registration/call; optional main/cli integration for performance APIs (currently commented in main.rs).
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## benchmark.rs
| Location | Comment / behavior | Real-world direction | Done |
|----------|--------------------|----------------------|------|
| ~135–138 | "Simple memory usage estimation" — `get_memory_usage()` returns fixed `size_of::<usize>() * 1024`. | Use platform-specific APIs (e.g. `getrusage`, `/proc/self/status`, Windows process APIs) or allocator stats when available; document fallback. | ❌ |
| ~259–266 | "Simplified version since the actual runtime doesn't support this pattern" — runtime benchmark "function_calls" uses println placeholders. | Wire to real runtime: register a `Function` (or equivalent), invoke via `Runtime::call_function` or execute_source; measure actual call cost. | ❌ |
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## profiler.rs
| Location | Comment / behavior | Real-world direction | Done |
|----------|--------------------|----------------------|------|
| ~191–193 | "Simple memory usage estimation" — `get_memory_usage()` returns fixed size. | Same as benchmark.rs: platform/allocator-based memory reporting; optional allocation tracking. | ❌ |
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## optimizer.rs
| Location | Comment / behavior | Real-world direction | Done |
|----------|--------------------|----------------------|------|
| ~366–369 | "Placeholder for loop optimizations" — `loop_optimization` returns clone + placeholder message. | Implement loop unrolling, loop-invariant code motion, induction variable simplification; integrate with AST loop constructs. | ❌ |
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## main.rs (performance API usage)
| Location | Comment / behavior | Real-world direction | Done |
|----------|--------------------|----------------------|------|
| ~25–32 | "Performance imports - kept for potential future use" — optimizer, memory, concurrency, benchmark, profiler imports commented out. | Optional: expose via CLI (e.g. `--bench`, `--profile`, `--optimize`) or feature-gated main path; keep test path as-is. | ❌ |
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## benches/
| Item | Comment / behavior | Real-world direction | Done |
|------|--------------------|----------------------|------|
| performance.rs | Criterion benchmarks for lexer, parser, runtime, stdlib, memory, concurrency. | Add parameterized sizes, throughput reporting, baseline comparison; consider CI integration. | ✅ Current |
| performance_benchmarks.rs | Additional Criterion benches (small/medium/large, parameterized). | Align naming/groups with performance.rs; single entrypoint or feature to select suite. | ✅ Current |
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## Suggested priority
1. **Medium** — **Runtime benchmark "function_calls":** Wire to real runtime registration and execution so the in-library benchmark measures actual function call cost; remove println placeholders.
2. **Medium** — **Memory usage:** Replace placeholder `get_memory_usage()` in benchmark.rs and profiler.rs with platform-specific or allocator-backed reporting; document fallback when unavailable.
3. **Lower** — **Loop optimizations:** Implement real loop_optimization in optimizer.rs (unrolling, invariant motion, etc.) and remove placeholder.
4. **Lower** — **Main/CLI:** Optionally enable performance imports and expose benchmark/profile/optimize via CLI or feature flag; keep test_performance_optimization() as primary in-process use.