Buckets:
| <meta charset="utf-8" /><meta name="hf:doc:metadata" content="{"title":"Continuous batching architecture","local":"continuous-batching-architecture","sections":[{"title":"Request lifecycle","local":"request-lifecycle","sections":[],"depth":2},{"title":"Chunked prefill","local":"chunked-prefill","sections":[],"depth":2},{"title":"Scheduler","local":"scheduler","sections":[{"title":"FIFO","local":"fifo","sections":[],"depth":3},{"title":"PrefillFirst","local":"prefillfirst","sections":[],"depth":3}],"depth":2},{"title":"CUDA graphs","local":"cuda-graphs","sections":[],"depth":2},{"title":"Async batching","local":"async-batching","sections":[],"depth":2},{"title":"Soft reset","local":"soft-reset","sections":[],"depth":2},{"title":"Next steps","local":"next-steps","sections":[],"depth":2}],"depth":1}"> | |
| <link href="/docs/transformers/pr_42227/en/_app/immutable/assets/0.e3b0c442.css" rel="modulepreload"> | |
| <link rel="modulepreload" href="/docs/transformers/pr_42227/en/_app/immutable/entry/start.a067d14a.js"> | |
| <link rel="modulepreload" href="/docs/transformers/pr_42227/en/_app/immutable/chunks/scheduler.31fdf58d.js"> | |
| <link rel="modulepreload" href="/docs/transformers/pr_42227/en/_app/immutable/chunks/singletons.303ebed4.js"> | |
| <link rel="modulepreload" href="/docs/transformers/pr_42227/en/_app/immutable/chunks/index.252883d5.js"> | |
| <link rel="modulepreload" href="/docs/transformers/pr_42227/en/_app/immutable/chunks/paths.afba2d50.js"> | |
| <link rel="modulepreload" href="/docs/transformers/pr_42227/en/_app/immutable/entry/app.95d76f53.js"> | |
| <link rel="modulepreload" href="/docs/transformers/pr_42227/en/_app/immutable/chunks/preload-helper.21822fa8.js"> | |
| <link rel="modulepreload" href="/docs/transformers/pr_42227/en/_app/immutable/chunks/index.2f76fdf0.js"> | |
| <link rel="modulepreload" href="/docs/transformers/pr_42227/en/_app/immutable/nodes/0.cb4700b8.js"> | |
| <link rel="modulepreload" href="/docs/transformers/pr_42227/en/_app/immutable/chunks/each.e59479a4.js"> | |
| <link rel="modulepreload" href="/docs/transformers/pr_42227/en/_app/immutable/nodes/35.56f9b5cd.js"> | |
| <link rel="modulepreload" href="/docs/transformers/pr_42227/en/_app/immutable/chunks/CopyLLMTxtMenu.bb5a0eb6.js"> | |
| <link rel="modulepreload" href="/docs/transformers/pr_42227/en/_app/immutable/chunks/MermaidChart.svelte_svelte_type_style_lang.d0fb4fa3.js"> | |
| <link rel="modulepreload" href="/docs/transformers/pr_42227/en/_app/immutable/chunks/IconCopy.ac192424.js"> | |
| <link rel="modulepreload" href="/docs/transformers/pr_42227/en/_app/immutable/chunks/CodeBlock.ab12f8e1.js"><!-- HEAD_svelte-u9bgzb_START --><meta name="hf:doc:metadata" content="{"title":"Continuous batching architecture","local":"continuous-batching-architecture","sections":[{"title":"Request lifecycle","local":"request-lifecycle","sections":[],"depth":2},{"title":"Chunked prefill","local":"chunked-prefill","sections":[],"depth":2},{"title":"Scheduler","local":"scheduler","sections":[{"title":"FIFO","local":"fifo","sections":[],"depth":3},{"title":"PrefillFirst","local":"prefillfirst","sections":[],"depth":3}],"depth":2},{"title":"CUDA graphs","local":"cuda-graphs","sections":[],"depth":2},{"title":"Async batching","local":"async-batching","sections":[],"depth":2},{"title":"Soft reset","local":"soft-reset","sections":[],"depth":2},{"title":"Next steps","local":"next-steps","sections":[],"depth":2}],"depth":1}"><!-- HEAD_svelte-u9bgzb_END --> <p></p> <div class="items-center shrink-0 min-w-[100px] max-sm:min-w-[50px] justify-end ml-auto flex" style="float: right; margin-left: 10px; display: inline-flex; position: relative; z-index: 10;"><div class="inline-flex rounded-md max-sm:rounded-sm"><button class="inline-flex items-center gap-1 h-7 max-sm:h-7 px-2 max-sm:px-1.5 text-sm font-medium text-gray-800 border border-r-0 rounded-l-md max-sm:rounded-l-sm border-gray-200 bg-white hover:shadow-inner dark:border-gray-850 dark:bg-gray-950 dark:text-gray-200 dark:hover:bg-gray-800" aria-live="polite"><span class="inline-flex items-center justify-center rounded-md p-0.5 max-sm:p-0 hover:text-gray-800 dark:hover:text-gray-200"><svg class="sm:size-3.5 size-3" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg></span> <span>Copy page</span></button> <button class="inline-flex items-center justify-center w-6 max-sm:w-5 h-7 max-sm:h-7 disabled:pointer-events-none text-sm text-gray-500 hover:text-gray-700 dark:hover:text-white rounded-r-md max-sm:rounded-r-sm border border-l transition border-gray-200 bg-white hover:shadow-inner dark:border-gray-850 dark:bg-gray-950 dark:text-gray-200 dark:hover:bg-gray-800" aria-haspopup="menu" aria-expanded="false" aria-label="Open copy menu"><svg class="transition-transform text-gray-400 overflow-visible sm:size-3.5 size-3 rotate-0" width="1em" height="1em" viewBox="0 0 12 7" fill="none" xmlns="http://www.w3.org/2000/svg"><path d="M1 1L6 6L11 1" stroke="currentColor"></path></svg></button></div> </div> <h1 class="relative group"><a id="continuous-batching-architecture" class="header-link block pr-1.5 text-lg no-hover:hidden with-hover:absolute with-hover:p-1.5 with-hover:opacity-0 with-hover:group-hover:opacity-100 with-hover:right-full" href="#continuous-batching-architecture"><span><svg class="" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 256 256"><path d="M167.594 88.393a8.001 8.001 0 0 1 0 11.314l-67.882 67.882a8 8 0 1 1-11.314-11.315l67.882-67.881a8.003 8.003 0 0 1 11.314 0zm-28.287 84.86l-28.284 28.284a40 40 0 0 1-56.567-56.567l28.284-28.284a8 8 0 0 0-11.315-11.315l-28.284 28.284a56 56 0 0 0 79.196 79.197l28.285-28.285a8 8 0 1 0-11.315-11.314zM212.852 43.14a56.002 56.002 0 0 0-79.196 0l-28.284 28.284a8 8 0 1 0 11.314 11.314l28.284-28.284a40 40 0 0 1 56.568 56.567l-28.285 28.285a8 8 0 0 0 11.315 11.314l28.284-28.284a56.065 56.065 0 0 0 0-79.196z" fill="currentColor"></path></svg></span></a> <span>Continuous batching architecture</span></h1> <p data-svelte-h="svelte-fmq6v9">Traditional batching processes a fixed group of requests together and waits for the slowest one to finish before starting the next group. This causes the GPU to idle between batches.</p> <p data-svelte-h="svelte-sidsim">With continuous batching, at every generation step, the scheduler checks for finished requests and replaces them immediately with waiting ones. Short requests are kicked out as soon as they’re done, and the GPU stays occupied the entire time. The result is significantly higher throughput and lower average latency.</p> <h2 class="relative group"><a id="request-lifecycle" class="header-link block pr-1.5 text-lg no-hover:hidden with-hover:absolute with-hover:p-1.5 with-hover:opacity-0 with-hover:group-hover:opacity-100 with-hover:right-full" href="#request-lifecycle"><span><svg class="" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 256 256"><path d="M167.594 88.393a8.001 8.001 0 0 1 0 11.314l-67.882 67.882a8 8 0 1 1-11.314-11.315l67.882-67.881a8.003 8.003 0 0 1 11.314 0zm-28.287 84.86l-28.284 28.284a40 40 0 0 1-56.567-56.567l28.284-28.284a8 8 0 0 0-11.315-11.315l-28.284 28.284a56 56 0 0 0 79.196 79.197l28.285-28.285a8 8 0 1 0-11.315-11.314zM212.852 43.14a56.002 56.002 0 0 0-79.196 0l-28.284 28.284a8 8 0 1 0 11.314 11.314l28.284-28.284a40 40 0 0 1 56.568 56.567l-28.285 28.285a8 8 0 0 0 11.315 11.314l28.284-28.284a56.065 56.065 0 0 0 0-79.196z" fill="currentColor"></path></svg></span></a> <span>Request lifecycle</span></h2> <p data-svelte-h="svelte-fcf2ao">A request moves through four states from submission to completion.</p> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START --> WAIT IN QUEUE LOAD PROMPT INTO KV STREAM OUTPUT DONE | |
| ┌────────────────┐ ┌─────────────────────┐ ┌─────────────────┐ ┌────────┐ | |
| │ PENDING │───▶│ PREFILLING │───▶│ DECODING │───▶│FINISHED│ | |
| │ ○ ○ ○ · · · │ │ ████████░░░░░░░░░░ │ │ → → → → · · │ │ ✓ │ | |
| └────────────────┘ └─────────────────────┘ └─────────────────┘ └────────┘ | |
| others ahead prompt chunks +1 token/step<!-- HTML_TAG_END --></pre></div> <ol data-svelte-h="svelte-1fhspt0"><li>Pending — the request is queued and waiting to be scheduled.</li> <li>Prefilling — prompt tokens are processed in a forward pass.</li> <li>Decoding — output tokens are generated one at a time.</li> <li>Finished — generation is complete and the result is available.</li></ol> <p data-svelte-h="svelte-qbwqi5">A request is moved from pending to prefilling when the scheduler finds enough token budget and cache space to admit the request. If the prompt is too long to fit in a single step, the scheduler splits it across multiple forward passes (chunk prefill).</p> <h2 class="relative group"><a id="chunked-prefill" class="header-link block pr-1.5 text-lg no-hover:hidden with-hover:absolute with-hover:p-1.5 with-hover:opacity-0 with-hover:group-hover:opacity-100 with-hover:right-full" href="#chunked-prefill"><span><svg class="" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 256 256"><path d="M167.594 88.393a8.001 8.001 0 0 1 0 11.314l-67.882 67.882a8 8 0 1 1-11.314-11.315l67.882-67.881a8.003 8.003 0 0 1 11.314 0zm-28.287 84.86l-28.284 28.284a40 40 0 0 1-56.567-56.567l28.284-28.284a8 8 0 0 0-11.315-11.315l-28.284 28.284a56 56 0 0 0 79.196 79.197l28.285-28.285a8 8 0 1 0-11.315-11.314zM212.852 43.14a56.002 56.002 0 0 0-79.196 0l-28.284 28.284a8 8 0 1 0 11.314 11.314l28.284-28.284a40 40 0 0 1 56.568 56.567l-28.285 28.285a8 8 0 0 0 11.315 11.314l28.284-28.284a56.065 56.065 0 0 0 0-79.196z" fill="currentColor"></path></svg></span></a> <span>Chunked prefill</span></h2> <p data-svelte-h="svelte-o2137r">Processing a long prompt in a single step is expensive because it blocks other requests from generating. Chunked prefill solves this by splitting large prefills across multiple steps.</p> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START -->Blocking (long prefill blocks the batch) | |
| Step: 1 2 3 4 | |
| Req A [▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓] ← one huge prefill | |
| Req B ················ wait ················ | |
| Req C ················ wait ················ | |
| Chunked (same prompt split and interleave with decode) | |
| Step: 1 2 3 4 | |
| Req A [▓▓ pre] [▓▓ pre] [▓▓ pre] [→ dec] | |
| Req B [→ dec] [→ dec] [▓▓ pre] [→ dec] | |
| Req C [→ dec] · idle · [→ dec] · idle ·<!-- HTML_TAG_END --></pre></div> <p data-svelte-h="svelte-1k7oy2">When a new request’s prompt exceeds the available token budget (set by <code>max_batch_tokens</code> in <a href="/docs/transformers/pr_42227/en/main_classes/continuous_batching#transformers.ContinuousBatchingConfig">ContinuousBatchingConfig</a>), the scheduler processes as many tokens as possible and holds the rest. On subsequent steps, it continues from where it left off, interleaving prefill work with ongoing decode steps. This keeps the batch productive and reduces time-to-first-token for other requests.</p> <h2 class="relative group"><a id="scheduler" class="header-link block pr-1.5 text-lg no-hover:hidden with-hover:absolute with-hover:p-1.5 with-hover:opacity-0 with-hover:group-hover:opacity-100 with-hover:right-full" href="#scheduler"><span><svg class="" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 256 256"><path d="M167.594 88.393a8.001 8.001 0 0 1 0 11.314l-67.882 67.882a8 8 0 1 1-11.314-11.315l67.882-67.881a8.003 8.003 0 0 1 11.314 0zm-28.287 84.86l-28.284 28.284a40 40 0 0 1-56.567-56.567l28.284-28.284a8 8 0 0 0-11.315-11.315l-28.284 28.284a56 56 0 0 0 79.196 79.197l28.285-28.285a8 8 0 1 0-11.315-11.314zM212.852 43.14a56.002 56.002 0 0 0-79.196 0l-28.284 28.284a8 8 0 1 0 11.314 11.314l28.284-28.284a40 40 0 0 1 56.568 56.567l-28.285 28.285a8 8 0 0 0 11.315 11.314l28.284-28.284a56.065 56.065 0 0 0 0-79.196z" fill="currentColor"></path></svg></span></a> <span>Scheduler</span></h2> <p data-svelte-h="svelte-u5rm2z">The scheduler decides which requests join each forward pass based on two budgets.</p> <ul data-svelte-h="svelte-zigvix"><li>Token budget — the maximum number of query tokens processed in a single forward pass, set by <code>max_batch_tokens</code> in <a href="/docs/transformers/pr_42227/en/main_classes/continuous_batching#transformers.ContinuousBatchingConfig">ContinuousBatchingConfig</a>.</li> <li>Cache budget — the total number of KV pages that can be read in a single pass, which is bounded by the total cache size.</li></ul> <h3 class="relative group"><a id="fifo" class="header-link block pr-1.5 text-lg no-hover:hidden with-hover:absolute with-hover:p-1.5 with-hover:opacity-0 with-hover:group-hover:opacity-100 with-hover:right-full" href="#fifo"><span><svg class="" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 256 256"><path d="M167.594 88.393a8.001 8.001 0 0 1 0 11.314l-67.882 67.882a8 8 0 1 1-11.314-11.315l67.882-67.881a8.003 8.003 0 0 1 11.314 0zm-28.287 84.86l-28.284 28.284a40 40 0 0 1-56.567-56.567l28.284-28.284a8 8 0 0 0-11.315-11.315l-28.284 28.284a56 56 0 0 0 79.196 79.197l28.285-28.285a8 8 0 1 0-11.315-11.314zM212.852 43.14a56.002 56.002 0 0 0-79.196 0l-28.284 28.284a8 8 0 1 0 11.314 11.314l28.284-28.284a40 40 0 0 1 56.568 56.567l-28.285 28.285a8 8 0 0 0 11.315 11.314l28.284-28.284a56.065 56.065 0 0 0 0-79.196z" fill="currentColor"></path></svg></span></a> <span>FIFO</span></h3> <p data-svelte-h="svelte-pu5t7g"><code>FIFOScheduler</code> is the default scheduler. It fills the batch in priority order. Active decode requests are processed first, then active prefill requests, and then new waiting requests in arrival order. This maximizes throughput by pushing existing requests through before pulling in new ones.</p> <h3 class="relative group"><a id="prefillfirst" class="header-link block pr-1.5 text-lg no-hover:hidden with-hover:absolute with-hover:p-1.5 with-hover:opacity-0 with-hover:group-hover:opacity-100 with-hover:right-full" href="#prefillfirst"><span><svg class="" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 256 256"><path d="M167.594 88.393a8.001 8.001 0 0 1 0 11.314l-67.882 67.882a8 8 0 1 1-11.314-11.315l67.882-67.881a8.003 8.003 0 0 1 11.314 0zm-28.287 84.86l-28.284 28.284a40 40 0 0 1-56.567-56.567l28.284-28.284a8 8 0 0 0-11.315-11.315l-28.284 28.284a56 56 0 0 0 79.196 79.197l28.285-28.285a8 8 0 1 0-11.315-11.314zM212.852 43.14a56.002 56.002 0 0 0-79.196 0l-28.284 28.284a8 8 0 1 0 11.314 11.314l28.284-28.284a40 40 0 0 1 56.568 56.567l-28.285 28.285a8 8 0 0 0 11.315 11.314l28.284-28.284a56.065 56.065 0 0 0 0-79.196z" fill="currentColor"></path></svg></span></a> <span>PrefillFirst</span></h3> <p data-svelte-h="svelte-1ldlqyp"><code>PrefillFirstScheduler</code> completes chunked prefill operations before resuming decode. This reduces fragmentation for workloads dominated by long prompts.</p> <p data-svelte-h="svelte-1608155">Set the scheduler in <a href="/docs/transformers/pr_42227/en/main_classes/continuous_batching#transformers.ContinuousBatchingConfig">ContinuousBatchingConfig</a>.</p> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START -->cb_config = ContinuousBatchingConfig(scheduler_type=<span class="hljs-string">"prefill_first"</span>)<!-- HTML_TAG_END --></pre></div> <h2 class="relative group"><a id="cuda-graphs" class="header-link block pr-1.5 text-lg no-hover:hidden with-hover:absolute with-hover:p-1.5 with-hover:opacity-0 with-hover:group-hover:opacity-100 with-hover:right-full" href="#cuda-graphs"><span><svg class="" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 256 256"><path d="M167.594 88.393a8.001 8.001 0 0 1 0 11.314l-67.882 67.882a8 8 0 1 1-11.314-11.315l67.882-67.881a8.003 8.003 0 0 1 11.314 0zm-28.287 84.86l-28.284 28.284a40 40 0 0 1-56.567-56.567l28.284-28.284a8 8 0 0 0-11.315-11.315l-28.284 28.284a56 56 0 0 0 79.196 79.197l28.285-28.285a8 8 0 1 0-11.315-11.314zM212.852 43.14a56.002 56.002 0 0 0-79.196 0l-28.284 28.284a8 8 0 1 0 11.314 11.314l28.284-28.284a40 40 0 0 1 56.568 56.567l-28.285 28.285a8 8 0 0 0 11.315 11.314l28.284-28.284a56.065 56.065 0 0 0 0-79.196z" fill="currentColor"></path></svg></span></a> <span>CUDA graphs</span></h2> <p data-svelte-h="svelte-ix78c4">Every generation step involves CPU overhead, from assembling the batch to dispatching GPU kernels and reading the results. CUDA graphs eliminate the overhead by recording the full GPU execution sequence once and replaying it for batches with matching shapes.</p> <p data-svelte-h="svelte-16idqdx">Because the batch shapes change every step, the continuous batching system handles this with padding and caching.</p> <ol data-svelte-h="svelte-19wnd24"><li>Query lengths are padded to the nearest multiple of <code>q_padding_interval_size</code>.</li> <li>KV lengths are padded to the nearest multiple of <code>kv_padding_interval_size</code>.</li> <li>Recorded graphs are stored in an LRU cache of up to <code>max_cached_graphs</code> entries.</li></ol> <p data-svelte-h="svelte-17u7u5a">When a batch’s padded shape matches a cached graph, the graph replays without any CPU dispatch. New shapes trigger a new graph capture.</p> <p data-svelte-h="svelte-1bi7ye1">CUDA graphs require static control flow and are incompatible with attention masks. They’re auto-detected by default and disabled when conditions aren’t met.</p> <h2 class="relative group"><a id="async-batching" class="header-link block pr-1.5 text-lg no-hover:hidden with-hover:absolute with-hover:p-1.5 with-hover:opacity-0 with-hover:group-hover:opacity-100 with-hover:right-full" href="#async-batching"><span><svg class="" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 256 256"><path d="M167.594 88.393a8.001 8.001 0 0 1 0 11.314l-67.882 67.882a8 8 0 1 1-11.314-11.315l67.882-67.881a8.003 8.003 0 0 1 11.314 0zm-28.287 84.86l-28.284 28.284a40 40 0 0 1-56.567-56.567l28.284-28.284a8 8 0 0 0-11.315-11.315l-28.284 28.284a56 56 0 0 0 79.196 79.197l28.285-28.285a8 8 0 1 0-11.315-11.314zM212.852 43.14a56.002 56.002 0 0 0-79.196 0l-28.284 28.284a8 8 0 1 0 11.314 11.314l28.284-28.284a40 40 0 0 1 56.568 56.567l-28.285 28.285a8 8 0 0 0 11.315 11.314l28.284-28.284a56.065 56.065 0 0 0 0-79.196z" fill="currentColor"></path></svg></span></a> <span>Async batching</span></h2> <p data-svelte-h="svelte-1045c3v">Async batching uses two I/O buffer pairs and two CUDA streams to overlap CPU and GPU work.</p> <div class="code-block relative "><div class="absolute top-2.5 right-4"><button class="inline-flex items-center relative text-sm focus:text-green-500 cursor-pointer focus:outline-none transition duration-200 ease-in-out opacity-0 mx-0.5 text-gray-600 " title="code excerpt" type="button"><svg class="" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z" transform="translate(0)"></path><path d="M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z" transform="translate(0)"></path><rect fill="none" width="32" height="32"></rect></svg> <div class="absolute pointer-events-none transition-opacity bg-black text-white py-1 px-2 leading-tight rounded font-normal shadow left-1/2 top-full transform -translate-x-1/2 translate-y-2 opacity-0"><div class="absolute bottom-full left-1/2 transform -translate-x-1/2 w-0 h-0 border-black border-4 border-t-0" style="border-left-color: transparent; border-right-color: transparent; "></div> Copied</div></button></div> <pre class=""><!-- HTML_TAG_START -->Sequential | |
| CPU ── [prep N] ·········idle········· [prep N+1] ·········idle········· | |
| GPU ·········idle········· [compute N] ·········idle········· [compute N+1] | |
| Async | |
| CPU ── [prep N] [prep N+1] [prep N+2] ── | |
| GPU ── ········ [compute N] [compute N+1] ──<!-- HTML_TAG_END --></pre></div> <p data-svelte-h="svelte-1j19cdl">While the GPU computes batch N, the CPU prepares batch N+1. However, overlapping the two requires roughly double the VRAM.</p> <p data-svelte-h="svelte-1un8fet">Async batching requires CUDA graphs to be active, since graph replay provides the stable tensor addresses needed for stream overlap to be correct.</p> <h2 class="relative group"><a id="soft-reset" class="header-link block pr-1.5 text-lg no-hover:hidden with-hover:absolute with-hover:p-1.5 with-hover:opacity-0 with-hover:group-hover:opacity-100 with-hover:right-full" href="#soft-reset"><span><svg class="" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 256 256"><path d="M167.594 88.393a8.001 8.001 0 0 1 0 11.314l-67.882 67.882a8 8 0 1 1-11.314-11.315l67.882-67.881a8.003 8.003 0 0 1 11.314 0zm-28.287 84.86l-28.284 28.284a40 40 0 0 1-56.567-56.567l28.284-28.284a8 8 0 0 0-11.315-11.315l-28.284 28.284a56 56 0 0 0 79.196 79.197l28.285-28.285a8 8 0 1 0-11.315-11.314zM212.852 43.14a56.002 56.002 0 0 0-79.196 0l-28.284 28.284a8 8 0 1 0 11.314 11.314l28.284-28.284a40 40 0 0 1 56.568 56.567l-28.285 28.285a8 8 0 0 0 11.315 11.314l28.284-28.284a56.065 56.065 0 0 0 0-79.196z" fill="currentColor"></path></svg></span></a> <span>Soft reset</span></h2> <p data-svelte-h="svelte-1ylfauv">If the KV cache fills completely during a long session, because requests are generating very long outputs, the manager triggers a soft reset rather than crashing. It selects the oldest active request (or the newest, if a previous soft reset already blocked new requests from joining), appends its generated tokens to its original prompt, frees its cache blocks, and adds it back to the queue.</p> <p data-svelte-h="svelte-iptwb5">When the cache has space again, the request resumes from where it left off with its generation history encoded in the prompt.</p> <h2 class="relative group"><a id="next-steps" class="header-link block pr-1.5 text-lg no-hover:hidden with-hover:absolute with-hover:p-1.5 with-hover:opacity-0 with-hover:group-hover:opacity-100 with-hover:right-full" href="#next-steps"><span><svg class="" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 256 256"><path d="M167.594 88.393a8.001 8.001 0 0 1 0 11.314l-67.882 67.882a8 8 0 1 1-11.314-11.315l67.882-67.881a8.003 8.003 0 0 1 11.314 0zm-28.287 84.86l-28.284 28.284a40 40 0 0 1-56.567-56.567l28.284-28.284a8 8 0 0 0-11.315-11.315l-28.284 28.284a56 56 0 0 0 79.196 79.197l28.285-28.285a8 8 0 1 0-11.315-11.314zM212.852 43.14a56.002 56.002 0 0 0-79.196 0l-28.284 28.284a8 8 0 1 0 11.314 11.314l28.284-28.284a40 40 0 0 1 56.568 56.567l-28.285 28.285a8 8 0 0 0 11.315 11.314l28.284-28.284a56.065 56.065 0 0 0 0-79.196z" fill="currentColor"></path></svg></span></a> <span>Next steps</span></h2> <ul data-svelte-h="svelte-1bjm8o9"><li>The <a href="https://huggingface.co/blog/continuous_batching" rel="nofollow">Continuous batching blog post</a> covers KV caching, chunked prefill, and dynamic scheduling with performance benchmark numbers.</li> <li>For usage examples, see the <a href="./continuous_batching">Continuous batching</a> doc.</li></ul> <a class="!text-gray-400 !no-underline text-sm flex items-center not-prose mt-4" href="https://github.com/huggingface/transformers/blob/main/docs/source/en/continuous_batching_architecture.md" target="_blank"><svg class="mr-1" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" fill="currentColor" focusable="false" role="img" width="1em" height="1em" preserveAspectRatio="xMidYMid meet" viewBox="0 0 32 32"><path d="M31,16l-7,7l-1.41-1.41L28.17,16l-5.58-5.59L24,9l7,7z"></path><path d="M1,16l7-7l1.41,1.41L3.83,16l5.58,5.59L8,23l-7-7z"></path><path d="M12.419,25.484L17.639,6.552l1.932,0.518L14.351,26.002z"></path></svg> <span data-svelte-h="svelte-zjs2n5"><span class="underline">Update</span> on GitHub</span></a> <p></p> | |
| <script> | |
| { | |
| __sveltekit_13nnzth = { | |
| assets: "/docs/transformers/pr_42227/en", | |
| base: "/docs/transformers/pr_42227/en", | |
| env: {} | |
| }; | |
| const element = document.currentScript.parentElement; | |
| const data = [null,null]; | |
| Promise.all([ | |
| import("/docs/transformers/pr_42227/en/_app/immutable/entry/start.a067d14a.js"), | |
| import("/docs/transformers/pr_42227/en/_app/immutable/entry/app.95d76f53.js") | |
| ]).then(([kit, app]) => { | |
| kit.start(app, element, { | |
| node_ids: [0, 35], | |
| data, | |
| form: null, | |
| error: null | |
| }); | |
| }); | |
| } | |
| </script> | |
Xet Storage Details
- Size:
- 31.4 kB
- Xet hash:
- 47499899285bb736805bd1581d13ff6ff4a03809fe342307cdb0a301ad01b4c2
·
Xet efficiently stores files, intelligently splitting them into unique chunks and accelerating uploads and downloads. More info.