Before it
Every attention head kept its own keys and values, all cached during generation.
The problem
The KV cache dominates memory during inference and throttles throughput.
What it introduced
Share one set of keys and values across all heads, shrinking the cache dramatically.
Why it matters
The start of the inference-efficiency line that runs through GQA to DeepSeek's latent attention.
What modern models inherit
KV cache design, the main memory constraint when you serve a model.
What came next
Grouped-query attention in 2023 found the middle ground that Llama 2 and Mistral adopted.