| <!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="Source of the Rust file `crates/profile/src/stop_watch.rs`."><title>stop_watch.rs - source</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-77263533.css"><meta name="rustdoc-vars" data-root-path="../../" data-static-root-path="../../static.files/" data-current-crate="profile" data-themes="" data-resource-suffix="" data-rustdoc-version="1.94.0 (4a4ef493e 2026-03-02)" data-channel="1.94.0" data-search-js="search-9e2438ea.js" data-stringdex-js="stringdex-b897f86f.js" data-settings-js="settings-c38705f0.js" ><script src="../../static.files/storage-e2aeef58.js"></script><script defer src="../../static.files/src-script-813739b1.js"></script><script defer src="../../src-files.js"></script><script defer src="../../static.files/main-7bab91a1.js"></script><noscript><link rel="stylesheet" href="../../static.files/noscript-ffcac47a.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 src"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="src-sidebar-title"><h2>Files</h2></div></nav><div class="sidebar-resizer" title="Drag to resize sidebar"></div><main><section id="main-content" class="content"><div class="main-heading"><h1><div class="sub-heading">profile/</div>stop_watch.rs</h1><rustdoc-toolbar></rustdoc-toolbar></div><div class="example-wrap digits-2"><pre class="rust"><code><a href=#1 id=1 data-nosnippet>1</a><span class="doccomment">//! Like `std::time::Instant`, but also measures memory & CPU cycles. |
| <a href=#2 id=2 data-nosnippet>2</a> |
| <a href=#3 id=3 data-nosnippet>3</a></span><span class="attr">#![allow(clippy::print_stderr)] |
| <a href=#4 id=4 data-nosnippet>4</a> |
| <a href=#5 id=5 data-nosnippet>5</a></span><span class="kw">use </span>std::{ |
| <a href=#6 id=6 data-nosnippet>6</a> fmt, |
| <a href=#7 id=7 data-nosnippet>7</a> time::{Duration, Instant}, |
| <a href=#8 id=8 data-nosnippet>8</a>}; |
| <a href=#9 id=9 data-nosnippet>9</a> |
| <a href=#10 id=10 data-nosnippet>10</a><span class="kw">use </span><span class="kw">crate</span>::MemoryUsage; |
| <a href=#11 id=11 data-nosnippet>11</a> |
| <a href=#12 id=12 data-nosnippet>12</a><span class="kw">pub struct </span>StopWatch { |
| <a href=#13 id=13 data-nosnippet>13</a> time: Instant, |
| <a href=#14 id=14 data-nosnippet>14</a> <span class="attr">#[cfg(all(target_os = <span class="string">"linux"</span>, not(target_env = <span class="string">"ohos"</span>)))] |
| <a href=#15 id=15 data-nosnippet>15</a> </span>counter: <span class="prelude-ty">Option</span><perf_event::Counter>, |
| <a href=#16 id=16 data-nosnippet>16</a> memory: MemoryUsage, |
| <a href=#17 id=17 data-nosnippet>17</a>} |
| <a href=#18 id=18 data-nosnippet>18</a> |
| <a href=#19 id=19 data-nosnippet>19</a><span class="kw">pub struct </span>StopWatchSpan { |
| <a href=#20 id=20 data-nosnippet>20</a> <span class="kw">pub </span>time: Duration, |
| <a href=#21 id=21 data-nosnippet>21</a> <span class="kw">pub </span>instructions: <span class="prelude-ty">Option</span><u64>, |
| <a href=#22 id=22 data-nosnippet>22</a> <span class="kw">pub </span>memory: MemoryUsage, |
| <a href=#23 id=23 data-nosnippet>23</a>} |
| <a href=#24 id=24 data-nosnippet>24</a> |
| <a href=#25 id=25 data-nosnippet>25</a><span class="kw">impl </span>StopWatch { |
| <a href=#26 id=26 data-nosnippet>26</a> <span class="kw">pub fn </span>start() -> StopWatch { |
| <a href=#27 id=27 data-nosnippet>27</a> <span class="attr">#[cfg(all(target_os = <span class="string">"linux"</span>, not(target_env = <span class="string">"ohos"</span>)))] |
| <a href=#28 id=28 data-nosnippet>28</a> </span><span class="kw">let </span>counter = { |
| <a href=#29 id=29 data-nosnippet>29</a> <span class="comment">// When debugging rust-analyzer using rr, the perf-related syscalls cause it to abort. |
| <a href=#30 id=30 data-nosnippet>30</a> // We allow disabling perf by setting the env var `RA_DISABLE_PERF`. |
| <a href=#31 id=31 data-nosnippet>31</a> |
| <a href=#32 id=32 data-nosnippet>32</a> </span><span class="kw">use </span>std::sync::OnceLock; |
| <a href=#33 id=33 data-nosnippet>33</a> <span class="kw">static </span>PERF_ENABLED: OnceLock<bool> = OnceLock::new(); |
| <a href=#34 id=34 data-nosnippet>34</a> |
| <a href=#35 id=35 data-nosnippet>35</a> <span class="kw">if </span><span class="kw-2">*</span>PERF_ENABLED.get_or_init(|| std::env::var_os(<span class="string">"RA_DISABLE_PERF"</span>).is_none()) { |
| <a href=#36 id=36 data-nosnippet>36</a> <span class="kw">let </span><span class="kw-2">mut </span>counter = perf_event::Builder::new() |
| <a href=#37 id=37 data-nosnippet>37</a> .build() |
| <a href=#38 id=38 data-nosnippet>38</a> .map_err(|err| <span class="macro">eprintln!</span>(<span class="string">"Failed to create perf counter: {err}"</span>)) |
| <a href=#39 id=39 data-nosnippet>39</a> .ok(); |
| <a href=#40 id=40 data-nosnippet>40</a> <span class="kw">if let </span><span class="prelude-val">Some</span>(counter) = <span class="kw-2">&mut </span>counter |
| <a href=#41 id=41 data-nosnippet>41</a> && <span class="kw">let </span><span class="prelude-val">Err</span>(err) = counter.enable() |
| <a href=#42 id=42 data-nosnippet>42</a> { |
| <a href=#43 id=43 data-nosnippet>43</a> <span class="macro">eprintln!</span>(<span class="string">"Failed to start perf counter: {err}"</span>) |
| <a href=#44 id=44 data-nosnippet>44</a> } |
| <a href=#45 id=45 data-nosnippet>45</a> counter |
| <a href=#46 id=46 data-nosnippet>46</a> } <span class="kw">else </span>{ |
| <a href=#47 id=47 data-nosnippet>47</a> <span class="prelude-val">None |
| <a href=#48 id=48 data-nosnippet>48</a> </span>} |
| <a href=#49 id=49 data-nosnippet>49</a> }; |
| <a href=#50 id=50 data-nosnippet>50</a> <span class="kw">let </span>memory = MemoryUsage::now(); |
| <a href=#51 id=51 data-nosnippet>51</a> <span class="kw">let </span>time = Instant::now(); |
| <a href=#52 id=52 data-nosnippet>52</a> StopWatch { |
| <a href=#53 id=53 data-nosnippet>53</a> time, |
| <a href=#54 id=54 data-nosnippet>54</a> <span class="attr">#[cfg(all(target_os = <span class="string">"linux"</span>, not(target_env = <span class="string">"ohos"</span>)))] |
| <a href=#55 id=55 data-nosnippet>55</a> </span>counter, |
| <a href=#56 id=56 data-nosnippet>56</a> memory, |
| <a href=#57 id=57 data-nosnippet>57</a> } |
| <a href=#58 id=58 data-nosnippet>58</a> } |
| <a href=#59 id=59 data-nosnippet>59</a> |
| <a href=#60 id=60 data-nosnippet>60</a> <span class="kw">pub fn </span>elapsed(<span class="kw-2">&mut </span><span class="self">self</span>) -> StopWatchSpan { |
| <a href=#61 id=61 data-nosnippet>61</a> <span class="kw">let </span>time = <span class="self">self</span>.time.elapsed(); |
| <a href=#62 id=62 data-nosnippet>62</a> |
| <a href=#63 id=63 data-nosnippet>63</a> <span class="attr">#[cfg(all(target_os = <span class="string">"linux"</span>, not(target_env = <span class="string">"ohos"</span>)))] |
| <a href=#64 id=64 data-nosnippet>64</a> </span><span class="kw">let </span>instructions = <span class="self">self</span>.counter.as_mut().and_then(|it| { |
| <a href=#65 id=65 data-nosnippet>65</a> it.read().map_err(|err| <span class="macro">eprintln!</span>(<span class="string">"Failed to read perf counter: {err}"</span>)).ok() |
| <a href=#66 id=66 data-nosnippet>66</a> }); |
| <a href=#67 id=67 data-nosnippet>67</a> <span class="attr">#[cfg(all(target_os = <span class="string">"linux"</span>, target_env = <span class="string">"ohos"</span>))] |
| <a href=#68 id=68 data-nosnippet>68</a> </span><span class="kw">let </span>instructions = <span class="prelude-val">None</span>; |
| <a href=#69 id=69 data-nosnippet>69</a> <span class="attr">#[cfg(not(target_os = <span class="string">"linux"</span>))] |
| <a href=#70 id=70 data-nosnippet>70</a> </span><span class="kw">let </span>instructions = <span class="prelude-val">None</span>; |
| <a href=#71 id=71 data-nosnippet>71</a> |
| <a href=#72 id=72 data-nosnippet>72</a> <span class="kw">let </span>memory = MemoryUsage::now() - <span class="self">self</span>.memory; |
| <a href=#73 id=73 data-nosnippet>73</a> StopWatchSpan { time, instructions, memory } |
| <a href=#74 id=74 data-nosnippet>74</a> } |
| <a href=#75 id=75 data-nosnippet>75</a>} |
| <a href=#76 id=76 data-nosnippet>76</a> |
| <a href=#77 id=77 data-nosnippet>77</a><span class="kw">impl </span>fmt::Display <span class="kw">for </span>StopWatchSpan { |
| <a href=#78 id=78 data-nosnippet>78</a> <span class="kw">fn </span>fmt(<span class="kw-2">&</span><span class="self">self</span>, f: <span class="kw-2">&mut </span>fmt::Formatter<<span class="lifetime">'_</span>>) -> fmt::Result { |
| <a href=#79 id=79 data-nosnippet>79</a> <span class="macro">write!</span>(f, <span class="string">"{:.2?}"</span>, <span class="self">self</span>.time)<span class="question-mark">?</span>; |
| <a href=#80 id=80 data-nosnippet>80</a> <span class="kw">if let </span><span class="prelude-val">Some</span>(<span class="kw-2">mut </span>instructions) = <span class="self">self</span>.instructions { |
| <a href=#81 id=81 data-nosnippet>81</a> <span class="kw">let </span><span class="kw-2">mut </span>prefix = <span class="string">""</span>; |
| <a href=#82 id=82 data-nosnippet>82</a> <span class="kw">if </span>instructions > <span class="number">10000 </span>{ |
| <a href=#83 id=83 data-nosnippet>83</a> instructions /= <span class="number">1000</span>; |
| <a href=#84 id=84 data-nosnippet>84</a> prefix = <span class="string">"k"</span>; |
| <a href=#85 id=85 data-nosnippet>85</a> } |
| <a href=#86 id=86 data-nosnippet>86</a> <span class="kw">if </span>instructions > <span class="number">10000 </span>{ |
| <a href=#87 id=87 data-nosnippet>87</a> instructions /= <span class="number">1000</span>; |
| <a href=#88 id=88 data-nosnippet>88</a> prefix = <span class="string">"m"</span>; |
| <a href=#89 id=89 data-nosnippet>89</a> } |
| <a href=#90 id=90 data-nosnippet>90</a> <span class="kw">if </span>instructions > <span class="number">10000 </span>{ |
| <a href=#91 id=91 data-nosnippet>91</a> instructions /= <span class="number">1000</span>; |
| <a href=#92 id=92 data-nosnippet>92</a> prefix = <span class="string">"g"</span>; |
| <a href=#93 id=93 data-nosnippet>93</a> } |
| <a href=#94 id=94 data-nosnippet>94</a> <span class="macro">write!</span>(f, <span class="string">", {instructions}{prefix}instr"</span>)<span class="question-mark">?</span>; |
| <a href=#95 id=95 data-nosnippet>95</a> } |
| <a href=#96 id=96 data-nosnippet>96</a> <span class="macro">write!</span>(f, <span class="string">", {}"</span>, <span class="self">self</span>.memory)<span class="question-mark">?</span>; |
| <a href=#97 id=97 data-nosnippet>97</a> <span class="prelude-val">Ok</span>(()) |
| <a href=#98 id=98 data-nosnippet>98</a> } |
| <a href=#99 id=99 data-nosnippet>99</a>} |
| </code></pre></div></section></main></body></html> |
