What's New in Inference Engineering — Philip Kiely, Baseten
Source
AI Engineer
Author
AI Engineer
Date
Key takeaways · AI-distilled
The talk's framing came from a real incident: TurboQuant reached 20 million people and dipped a memory-stock index because people assumed the KV cacheThe memory a model keeps about text it has already read, so generating each new token doesn't require reprocessing the whole conversation.Full definition → had halved, prompting Kiely's team to run the actual bandwidth-vs-compute math.
KV cache context compactionSummarizing an agent's earlier conversation to free room in the context window so a long session can keep going.Full definition → (distinct from quantizationShrinking a model by storing its numbers less precisely — like rounding — so it runs faster and fits on smaller hardware, at a small quality cost.Full definition →) uses a learned bottleneck that cross-attends fixed query vectors against the full KV cache to emit compact keys and values in a single forward pass.
Same-family small draft models made poor speculative decoders; training a drafter directly on the target model's hidden states worked far better, and a newer diffusion drafter proposes 8-16 tokens per step.
Days before the talk, a method paired the diffusion drafter with a sequential one, and continuously retraining the speculator on live prompts lifts acceptance 20% to 2x, if a team can afford the storage, compute, and permissions.
Kiely frames local inference work as 'get it working, then make it less dumb' versus data-center work as 'get it working, then make it less slow' -- and says data-center optimizations increasingly come out of a dedicated training process, blurring training and inference.
Terms in this piece · Glossary
KV cache — The memory a model keeps about text it has already read, so generating each new token doesn't require reprocessing the whole conversation.
speculative decoding — A speed trick where a small model drafts several tokens ahead and the big model verifies them in one pass, often doubling generation speed.
quantization — Shrinking a model by storing its numbers less precisely — like rounding — so it runs faster and fits on smaller hardware, at a small quality cost.
context compaction — Summarizing an agent's earlier conversation to free room in the context window so a long session can keep going.
Why it matters
Baseten's Philip Kiely explains why 4-bit KV cache quantization only makes sense on memory-starved local machines rather than in data centers, and describes a diffusion-based speculative decoder that more than tripled token acceptance in production.