⚡ KV Cache Optimization

Accelerate transformer inference with efficient key-value caching

Your Progress

0 / 5 completed
Previous Module
Layer Normalization

Why KV Cache?

🎯 The Problem

In autoregressive generation (GPT-style), models generate one token at a time. Without caching, each new token requires recomputing attention for all previous tokens – wasteful since those computations don't change!

💡
Key Insight

KV cache stores previously computed key and value matrices. For each new token, we only compute K and V for that token and append to cache – massive speedup!

❌ Without KV Cache

Token 1: "The"
Compute Q, K, V for position 0
Token 2: "cat"
Recompute Q, K, V for positions 0-1
Token 3: "sat"
Recompute Q, K, V for positions 0-2
⚠️ O(n²) redundant computation!

✅ With KV Cache

Token 1: "The"
Compute & cache K₀, V₀
Token 2: "cat"
Compute only K₁, V₁, append to cache
Token 3: "sat"
Compute only K₂, V₂, append to cache
✓ O(n) linear computation!

📊 Performance Impact

Speed
10-100x

Faster generation for long sequences

💾
Memory
2x

Overhead for caching K,V tensors

🎯
FLOPs
95%

Reduction in computation