BitNet on CPUs: Optional Backend for Gating and Edge
By Auspexi • September 2025 • 7 min read
Microsoft has released bitnet.cpp, a fast 1‑bit/ternary LLM inference framework for CPUs, alongside research on BitNet architectures (paper). For AethergenPlatform, this opens a practical path to CPU‑first deployments where GPUs are unavailable, air‑gapped, or reserved for heavier stages.
Positioning. We integrate BitNet as an optional CPU backend for selective prediction gates and retrieval re‑ranking. We report measured results on our workloads and hardware only. We do not make blanket performance or energy claims.
Why this matters
- Edge and air‑gapped. Run small decision models locally on x86 CPUs.
- Selective prediction. Accept easy cases on CPU; route hard cases to larger models.
- Retrieval re‑ranking. Improve context quality with a low‑latency CPU scorer.
- Operational simplicity. Fewer dependencies for on‑prem installs.
How we integrate
We added a CPU backend option to our demo and internal services:
- CPU runner client. A tiny adapter with /score and /rerank endpoints.
- Netlify proxy. A proxy function with a safe weighted‑score fallback when no runner is present.
- UI toggle. In the Stability & SLO demo, enable “Use CPU backend” to route calibration via the CPU path.
Try it locally. You can point the UI and proxy to a local BitNet HTTP wrapper. When no runner is available, the proxy falls back to a deterministic weighted score for demonstration.
Configuration
Add these environment variables if you run a local CPU runner service:
VITE_CPU_RUNNER_URL (frontend, e.g., http://localhost:8088)CPU_RUNNER_BASE (Netlify function, e.g., http://localhost:8088)
Then open the Stability demo and toggle Use CPU backend when calibrating selective prediction.
Reliability and evidence
- We calibrate thresholds from observed signals (margin/entropy/retrieval) and record results in evidence bundles.
- Unity Catalog comments and tags store configuration notes for auditability.
- All gating remains fail‑closed with SLOs and rollback rules unchanged.
Further reading
Call to action. If you need CPU‑first options in regulated or air‑gapped environments, we can help evaluate gating on your workloads and report measured outcomes.