KVarN: Variance-Normalized KV-Cache Quantization [R]

Excited to share some of my own work here KVarN is our new KV-Cache quantization method. In very brief, we combine Hadamard rotations with variance-normalization on both axes of the K and V matrices, then round to nearest. Simple, but works very well, especially for decode-heavy test-time-scaling settings (reasoning, code-gen, agentics). We get 3-4x compression at virtually no accuracy drop (mostly 0-1%) on tough benchmarks like AIME24 as well as a speed-up over fp16 baseline in vLLM (in contrast to other recent KV-Cache compression works.