Beyond Model Loading
Loading a model onto a GPU and accepting HTTP requests is the minimum viable inference setup, not a production serving pipeline. Production requires continuous batching to maximize GPU utilization, KV-cache management to handle long contexts efficiently, request routing for multi-model deployments, A/B testing infrastructure for model evaluation, and graceful degradation under load. The serving pipeline turns raw GPU compute into a reliable, measurable, and optimizable AI service.
vLLM with PagedAttention
Memory-efficient KV-cache management enables 2-4x higher throughput than naive serving. Continuous batching inserts new requests into running batches. OpenAI-compatible API for drop-in replacement of cloud APIs.
TGI (Text Generation Inference)
Hugging Face-maintained server with flash attention, speculative decoding, and grammar-constrained generation. Prometheus metrics out of the box. Strong community and regular updates aligned with the Hugging Face ecosystem.
Triton Inference Server
Multi-framework serving for LLMs, embedding models, classifiers, and custom models on shared infrastructure. Model ensembles chain preprocessing, inference, and postprocessing. Dynamic batching across model types.
Ollama for Development
Simple model management and serving for development and testing environments. Pull models with one command, serve via local API. Not production-grade but excellent for developer productivity and prototyping.
Serving Pipeline Architecture
Receive
API gateway with auth and rate limits
Route
Model selection and A/B assignment
Batch
Continuous batching and prioritization
Infer
GPU execution with KV-cache
Stream
SSE token streaming to client
Receive
API gateway with auth and rate limits
Route
Model selection and A/B assignment
Batch
Continuous batching and prioritization
Infer
GPU execution with KV-cache
Stream
SSE token streaming to client
Model Serving Pipeline
Continuous Batching and KV-Cache
The two most impactful optimizations in LLM serving are continuous batching and efficient KV-cache management. Together, they can increase throughput by 3-5x on the same hardware.
Continuous batching. Traditional batching waits until a batch is full or a timeout expires, then processes the entire batch. Continuous batching (iteration-level batching) inserts new requests into the running batch at every decode step. Short requests complete and free their resources while long requests continue generating. GPU utilization stays high regardless of request length distribution.
PagedAttention (vLLM). Traditional KV-cache allocation reserves contiguous memory for the maximum sequence length, wasting 60-80% of GPU memory on padding. PagedAttention allocates KV-cache in small non-contiguous pages, similar to operating system virtual memory. Memory utilization approaches 100%, enabling larger batch sizes and higher throughput.
Prefix caching. When multiple requests share the same system prompt or context prefix, the KV-cache for the shared prefix is computed once and reused. Particularly effective for RAG workloads where the system prompt plus retrieved context is identical across many user queries.
A/B Testing and Canary Deployments
Evaluating model quality in production requires routing a percentage of traffic to alternative models and comparing outcomes. The serving pipeline provides this capability without application changes.
Traffic splitting. Route 95% of traffic to the production model and 5% to a candidate model. Compare latency, output quality (via automated evaluation), and user satisfaction metrics. Gradually increase traffic to the candidate if metrics are favorable.
Shadow mode. Send requests to both models simultaneously but only return the production model's response. Log the candidate model's output for offline evaluation. Zero user impact during testing.
Who This Is For
Model serving pipeline design is for organizations that need reliable, high-performance AI inference in production. If you are past the proof-of-concept stage and need your AI to serve real users with consistent latency, high availability, and measurable quality, this is the infrastructure layer that delivers it.
Contact us at ben@oakenai.tech
