# JIT Performance Status

## Current Status: JIT NOT WORKING

### Problem Identified
**LLVM is not available** - The JIT compiler requires LLVM to be installed and configured.

### Evidence
- `config.h` shows: `/* #undef HAVE_LLVM */`
- `llvm-config` command not found on system
- Benchmark results show proprietary Octave (1.139s) is almost identical to original GPL Octave (1.153s)
- This indicates JIT compilation is **not happening**

### Performance Comparison
- **MATLAB**: 0.0015779s (722x faster)
- **Proprietary Octave**: 1.1394201756s (JIT not working)
- **Original GPL Octave**: 1.1530918121s

### Solution Required
1. **Install LLVM development libraries**:
   ```bash
   sudo apt-get install llvm-dev libllvm-dev
   ```

2. **Rebuild Octave with JIT enabled**:
   ```bash
   ./configure --enable-jit
   make -j4
   ```

3. **Verify LLVM is detected**:
   - Check `config.h` for `#define HAVE_LLVM 1`
   - Verify `llvm-config --version` works

### Code Status
✅ **JIT code is implemented correctly**:
- Static analysis for constant-bound loops
- Automatic JIT enablement when LLVM available
- Lazy compilation in `pt-eval.cc`
- Aggressive LLVM optimization passes

❌ **JIT cannot run without LLVM**:
- JIT compiler initializes but `m_codegen` is `nullptr`
- `m_enabled` is set to `false` when LLVM unavailable
- All functions fall back to interpreter

### Next Steps
1. Install LLVM
2. Rebuild Octave
3. Re-run benchmarks
4. Expected: Proprietary Octave should match or exceed MATLAB performance