Chapter 1. About Speculators

Speculators is a unified library for building, training, and storing speculative decoding algorithms for large language model (LLM) inference, including frameworks such as vLLM.

Speculative decoding is an optimization technique that improves inference performance for the LLM you are trying to serve. Red Hat AI Inference Server supports Eagle 3, a speculative decoding algorithm that uses a small, single-layer draft model and a full-sized 'verifier' model, which is the LLM you are serving. The Eagle 3 speculator model auto-regressively predicts several tokens, and then the verifier model processes these tokens in parallel. As the verifier model can accept multiple tokens per forward pass, effective throughput increases. When the verifier model rejects a token, it samples a corrected token from its own distribution, ensuring the output matches what it would produce alone.

Speculative decoding provides the following advantages: