| <!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Utility for writing benchmark tests."><title>bench in test_utils - Rust</title><script>if(window.location.protocol!=="file:")document.head.insertAdjacentHTML("beforeend","SourceSerif4-Regular-6b053e98.ttf.woff2,FiraSans-Italic-81dc35de.woff2,FiraSans-Regular-0fe48ade.woff2,FiraSans-MediumItalic-ccf7e434.woff2,FiraSans-Medium-e1aa3f0a.woff2,SourceCodePro-Regular-8badfe75.ttf.woff2,SourceCodePro-Semibold-aa29a496.ttf.woff2".split(",").map(f=>`<link rel="preload" as="font" type="font/woff2"href="../static.files/${f}">`).join(""))</script><link rel="stylesheet" href="../static.files/normalize-9960930a.css"><link rel="stylesheet" href="../static.files/rustdoc-e56847b5.css"><meta name="rustdoc-vars" data-root-path="../" data-static-root-path="../static.files/" data-current-crate="test_utils" data-themes="" data-resource-suffix="" data-rustdoc-version="1.91.1 (ed61e7d7e 2025-11-07)" data-channel="1.91.1" data-search-js="search-e256b49e.js" data-stringdex-js="stringdex-c3e638e9.js" data-settings-js="settings-c38705f0.js" ><script src="../static.files/storage-e2aeef58.js"></script><script defer src="sidebar-items.js"></script><script defer src="../static.files/main-6dc2a7f3.js"></script><noscript><link rel="stylesheet" href="../static.files/noscript-263c88ec.css"></noscript><link rel="alternate icon" type="image/png" href="../static.files/favicon-32x32-eab170b8.png"><link rel="icon" type="image/svg+xml" href="../static.files/favicon-044be391.svg"></head><body class="rustdoc fn"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><rustdoc-topbar><h2><a href="#">bench</a></h2></rustdoc-topbar><nav class="sidebar"><div class="sidebar-crate"><h2><a href="../test_utils/index.html">test_<wbr>utils</a><span class="version">0.0.0</span></h2></div><div class="sidebar-elems"><div id="rustdoc-modnav"></div></div></nav><div class="sidebar-resizer" title="Drag to resize sidebar"></div><main><div class="width-limiter"><section id="main-content" class="content"><div class="main-heading"><div class="rustdoc-breadcrumbs"><a href="index.html">test_utils</a></div><h1>Function <span class="fn">bench</span> <button id="copy-path" title="Copy item path to clipboard">Copy item path</button></h1><rustdoc-toolbar></rustdoc-toolbar><span class="sub-heading"><a class="src" href="../src/test_utils/lib.rs.html#458-471">Source</a> </span></div><pre class="rust item-decl"><code>pub fn bench(label: &'static <a class="primitive" href="https://doc.rust-lang.org/1.91.1/std/primitive.str.html">str</a>) -> impl <a class="trait" href="https://doc.rust-lang.org/1.91.1/core/ops/drop/trait.Drop.html" title="trait core::ops::drop::Drop">Drop</a></code></pre><details class="toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Utility for writing benchmark tests.</p> |
| <p>A benchmark test looks like this:</p> |
| |
| <div class="example-wrap ignore"><a href="#" class="tooltip" title="This example is not tested">ⓘ</a><pre class="rust rust-example-rendered"><code><span class="attr">#[test] |
| </span><span class="kw">fn </span>benchmark_foo() { |
| <span class="kw">if </span>skip_slow_tests() { <span class="kw">return</span>; } |
| |
| <span class="kw">let </span>data = bench_fixture::some_fixture(); |
| <span class="kw">let </span>analysis = some_setup(); |
| |
| <span class="kw">let </span>hash = { |
| <span class="kw">let </span>_b = bench(<span class="string">"foo"</span>); |
| actual_work(analysis) |
| }; |
| <span class="macro">assert_eq!</span>(hash, <span class="number">92</span>); |
| }</code></pre></div> |
| <ul> |
| <li>We skip benchmarks by default, to save time. |
| Ideal benchmark time is 800 – 1500 ms in debug.</li> |
| <li>We don’t count preparation as part of the benchmark</li> |
| <li>The benchmark itself returns some kind of numeric hash. |
| The hash is used as a sanity check that some code is actually run. |
| Otherwise, it’s too easy to win the benchmark by just doing nothing.</li> |
| </ul> |
| </div></details></section></div></main></body></html> |
