Continuous Batching — How vLLM Hits 10× Throughput
As of 2026-07-24T14:00:00Z
What is Continuous Batching — How vLLM Hits 10× Throughput?
Static batching wastes 60-90% of GPU compute because one long request in a batch forces the GPU to keep running padded slots for requests that finished early — continuous batching frees each slot the instant its request ends.
Continuous batching — also called iteration-level or in-flight batching — is the scheduling technique that lets an LLM inference engine start processing a new request the moment an older one finishes, rather than waiting for an entire batch to complete together. It is the single largest reason engines such as vLLM and TensorRT-LLM reach roughly ten to twenty-four times higher throughput than a naive text-generation loop running on the same GPU hardware, and it is worth understanding even for a non-engineer evaluating an SAP AI deployment, because it directly drives the cost-per-token and the response latency a consultant will be asked to explain to a client.
Why naive batching fails, and how the alternative works
Why it matters
- The scheduler reasons in iterations, not requests: it repacks the batch every forward pass, admitting a new pending request the moment any slot frees.
- Combined with PagedAttention, continuous batching keeps GPU utilization at 60-90% across requests of wildly different lengths, versus the massive waste of static batching.
- Throughput improves 5-10× at the same hardware budget, with P99 tail latency improving even more since short requests no longer queue behind long ones.
Key points
- Iteration-level scheduling — new requests admitted to the batch as soon as older ones finish, not at batch boundaries.
- Naive static batching wastes 60-90% of GPU compute on real workloads with variable output length.
- Combined with PagedAttention (C246), continuous batching keeps GPU at 60-90% effective utilisation across diverse-length requests.
- 10-24x throughput improvement over HuggingFace generate() baseline on the same hardware.
- P99 tail latency improves because short requests do not queue behind long ones.
- Implementation complexity is why most teams adopt vLLM or TensorRT-LLM rather than build their own scheduler.
- Continuous Batching — How vLLM Hits 10× Throughput is mastered only when it changes a named buyer decision.
- Start with the semantic contract and control model before demonstrating the tool.
- Use current SAP, analyst, study, KG, and news signals as evidence, not decoration.
- Separate verified facts from directional trends and modeled assumptions.
Terms used on this page
- Continuous batching
- Scheduling LLM inference at the iteration level so new requests are admitted into the batch as soon as older requests finish, rather than waiting for the whole batch to complete.
- Static batching
- The naive approach where a batch of requests is fixed at admission time and all step through forward passes together until the longest one finishes.
- Iteration-level scheduling
- Synonym for continuous batching; emphasises that scheduling decisions happen at every forward-pass iteration, not at request boundaries.
- Head-of-line blocking
- The latency problem in static batching where short requests must wait for the longest request in their batch to finish; eliminated by continuous batching.
- Decision owner
- The accountable person who accepts the trade-off and funds the next action.
- Semantic contract
- The shared definition of business terms, metrics, entities, and access rules used by tools and teams.
- Control plane
- The layer that applies policy, access, lineage, monitoring, and escalation across the operating model.
- Evidence grade
- A label that separates verified fact, directional signal, modeled assumption, and field observation.
Sources
- Yu et al. — Orca: A Distributed Serving System for Transformer-Based Generative Models (OSDI 2022, the iteration-batching paper)
- Kwon et al. — Efficient Memory Management for Large Language Model Serving with PagedAttention (SOSP 2023)
- NVIDIA TensorRT-LLM in-flight batching documentation
- Anyscale — How continuous batching enables 23x throughput in LLM inference
- SAP News Center — Accelerate the Autonomous Enterprise with SAP Business Data Cloud
- SAP News Center — SAP Unveils the Autonomous Enterprise
- SAP News Center — The Future of the Enterprise Is Autonomous
- SAP News Center — 2026 SAP Sapphire Keynote: Powering the Autonomous Enterprise
- SAP Datasphere — Help Portal
- SAP Datasphere — official product page
- SAP Analytics Cloud — Help Portal
- SAP Analytics Cloud — official product page
- SAP BW/4HANA — Help Portal
- SAP S/4HANA — Help Portal
- SAP News Center
- SAP Community
- SAP — industries overview
- Gartner — research & analyst site
- BARC — BI & Analytics research
- TDWI — data & analytics research
- DSAG — German-speaking SAP user group
- ASUG — Americas' SAP User Group
- Databricks — official site
- Databricks — LLM inference performance engineering best practices
- NVIDIA Docs — TensorRT-LLM
Full card available to members. What the full card adds: the full decision framework · the SAP vs Snowflake / Databricks / Fabric comparison · the common pitfalls and their fix · the cheat sheet · the architecture schemas · the code blocks · the facts worth quoting.