A systems programming language designed for energy-efficient computing.
The global computing infrastructure now consumes approximately 4-5% of global electricity production, with data centers alone using 240-340 TWh annually. Research shows that programming language choice can result in energy consumption differences of up to 75x for equivalent computations.
Joule addresses this by making energy efficiency a first-class language concern, not an afterthought.
@energy_budget(100.microjoules)
fn process_sensor_reading(data: &SensorData) -> ProcessedData {
// Compiler estimates energy bounds; warns if budget may be exceeded
...
}
- Energy budgets as language primitives
- Compile-time estimation of energy consumption
- Runtime measurement via Intel RAPL, ARM Energy Probe
Joule uses an ownership and borrowing system for deterministic memory management:
- No garbage collector pauses or energy spikes
- Memory safety verified at compile time
- Energy efficiency comparable to C/C++
First-class support for GPUs, TPUs, and AI accelerators:
@kernel
fn matrix_multiply(a: &Matrix, b: &Matrix) -> Matrix {
// Implementation compiles for CPU, GPU, and TPU
parallel_for (i, j) in (0..a.rows, 0..b.cols) {
result[i][j] = dot(a.row(i), b.col(j))
}
}
| Backend | Use Case | Characteristics |
|---|---|---|
| Cranelift | Development | Fast compilation for rapid iteration |
| LLVM | Production | Maximum optimization, broad platform support |
| MLIR | AI Hardware | TPUs, NPUs, emerging accelerators |
| Document | Description |
|---|---|
| The Joule Story | Origins and motivation behind Joule |
| Technical Overview | Language features and architecture |
| Energy Crisis in Computing | Computing's energy footprint and solutions |
| Sustainable Computing Manifesto | Principles for energy-aware development |
| Aspect | Rust | Joule |
|---|---|---|
| Primary goal | Memory safety | Energy efficiency |
| Energy visibility | External tools only | First-class (@energy_budget) |
| Heterogeneous compute | Via external libraries | First-class (@kernel, @target(GPU)) |
| Hardware telemetry | Manual integration | Built-in RAPL/thermal awareness |
| Compiler backends | LLVM only | Cranelift + LLVM + MLIR |
Rust remains excellent for safety-critical systems. Joule is designed for energy-critical systems where sustainability and hardware efficiency are primary concerns.
- Linux x86_64, arm64
- macOS x86_64, arm64 (Apple Silicon)
- Windows x86_64, arm64
- FreeBSD x86_64
- WebAssembly (wasm32)
Joule is currently in early development. We are building the compiler infrastructure and core language features.
Joule is developed and maintained by Open Interface Engineering, Inc.
Joule is licensed under the Apache License 2.0. See LICENSE for details.
- Website: joule-lang.org
- Organization: Open Interface Engineering, Inc.
- Contact: david@openie.dev
"Every operation has a cost, and that cost matters."
Named after James Prescott Joule (1818-1889), who established the mechanical equivalent of heat and laid the foundation for the first law of thermodynamics.