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2025-05-03Inference Characteristics of Llama
A primer on inference math and an examination of the surprising costs of Llama.
By Aman19 minutes read
Inference Characteristics of Llama
While LLaMA models are known for strong performance, inference costs can scale quickly depending on deployment setup. This post explores why.
The Math Behind Inference
Each token generation involves:
- A forward pass through the entire transformer stack
- KV cache operations that scale with sequence length
- Attention mechanisms that become increasingly expensive
Surprising Bottlenecks
Llama’s inference isn't just GPU-bound:
- Memory bandwidth limits token throughput
- Prefill vs. decode stage ratio becomes significant
- Context length directly increases compute cost per token
Optimization Techniques
- Use quantization or FlashAttention for improved efficiency
- Cache early layer activations for long contexts
- Choose batch sizes carefully to maximize throughput
Llama may be free, but inference is not. Understanding the bottlenecks is key to efficient deployment.