Show HN: A Zero-Copy 1.58-bit LLM Engine hitting 117 Tokens/s on single CPU core
dhilipsiva Sunday, January 25, 2026
The Project: I am building R3-Engine, a from-scratch, local AI inference engine for Microsoft's bitnet-b1.58-2B-4T. It is written in 100% Safe Rust, natively cross-compiles to Wasm SIMD128, and uses Zero heap allocations in the execution loop.
The Physics: By mapping a 64-byte aligned .r3 file directly from NVMe to CPU L3 Cache (Zero-Copy) and using AVX-512 VPOPCNTDQ for branchless math, the Ryzen 9950X3D achieves 117 Tokens/Second latency.
The Problem: The AI is mute (Outputting <unk>*)* The matrix multiplication pipeline is mathematically complete, but the output is stuck at Token ID 0 (<unk>). The issue lies in the transition between the quantized weights and the float-based non-linear activations.
Where I need expert input:
Weight Tying in BitNet: Microsoft's 2B model ties Embeddings with the LM Head. I am cloning the embedding matrix for the output projection, but I suspect a scaling factor is missing.
RMSNorm & SiLU in 1.58-bit: How should the raw integer accumulators (from the VPOPCNTDQ loop) be scaled before entering the SiLU activation and the subsequent layer?
If you know the physics of LLM Logit Sampling or ternary activation math, I would love your eyes on the codebase.