deploy: 6632848833

2026-01-14 12:35:00 +01:00 · 2022-07-23 19:18:15 +00:00 · 2022-07-23 19:18:15 +00:00 · 73d8f12885
commit 73d8f12885
parent 690a515f92
5 changed files with 6 additions and 6 deletions
--- a/index.xml
+++ b/index.xml
@ -153,7 +153,7 @@ don&amp;rsquo;t think this can reasonable be changed.&lt;/p>
 that can bring clear performance wins (for &lt;code>noalias&lt;/code> on &lt;code>&amp;amp;mut T&lt;/code>, those were measureable). So the only question remains:
 &lt;strong>How much performance does &lt;code>noalias&lt;/code> on &lt;code>Box&amp;lt;T&amp;gt;&lt;/code> give us now, and how many potential performance improvements could we get in the
 future?&lt;/strong> For the latter, there is no simple answer. For the former, there is. &lt;code>rustc&lt;/code> has &lt;a href="https://github.com/rust-lang/rust/pull/99527">&lt;em>no&lt;/em> performance improvements&lt;/a>
-from being compiled with &lt;code>noalias&lt;/code> on &lt;code>Box&amp;lt;T&amp;gt;&lt;/code>.&lt;/p>
+from being compiled with &lt;code>noalias&lt;/code> on &lt;code>Box&amp;lt;T&amp;gt;&lt;/code>, but this isn&amp;rsquo;t really representative since rustc mostly uses arenas instead of box internally.&lt;/p>
 &lt;p>I have also benchmarked a few crates from the ecosystem with and without noalias on box, and the &lt;a href="https://gist.github.com/Nilstrieb/9a0751fb9fd1044a30ab55cef9a7d335">results&lt;/a>
 were inconclusive. (At the time of writing, only regex-syntax, tokio, and syn have been benchmarked.) regex-syntax showed no changes. Tokio showed a few improvements without noalias
 which is very weird, so maybe the benchmarks aren&amp;rsquo;t really good or something else was going on. And syn tended towards minor regressions without noalias, but the benchmarks had high
--- a/posts/box-is-a-unique-type/index.html
+++ b/posts/box-is-a-unique-type/index.html
@ -1,6 +1,6 @@
 <!doctype html><html lang=en><head><title>Box Is a Unique Type :: nilstriebs blog</title><meta charset=utf-8><meta name=viewport content="width=device-width,initial-scale=1"><meta name=description content="About better aliasing semantics for `Box`"><meta name=keywords content="box,noalias"><meta name=robots content="noodp"><link rel=canonical href=/posts/box-is-a-unique-type/><link rel=stylesheet href=/assets/style.css><link rel=apple-touch-icon href=/img/apple-touch-icon-192x192.png><link rel="shortcut icon" href=/img/favicon/orange.png><meta name=twitter:card content="summary"><meta property="og:locale" content="en"><meta property="og:type" content="article"><meta property="og:title" content="Box Is a Unique Type"><meta property="og:description" content="About better aliasing semantics for `Box`"><meta property="og:url" content="/posts/box-is-a-unique-type/"><meta property="og:site_name" content="nilstriebs blog"><meta property="og:image" content="/img/favicon/orange.png"><meta property="og:image:width" content="2048"><meta property="og:image:height" content="1024"><meta property="article:published_time" content="2022-07-23 00:00:00 +0000 UTC"></head><body class=orange><div class="container center headings--one-size"><header class=header><div class=header__inner><div class=header__logo><a href=/><div class=logo>nilstriebs blog</div></a></div></div></header><div class=content><div class=post><h1 class=post-title><a href=/posts/box-is-a-unique-type/>Box Is a Unique Type</a></h1><div class=post-meta><span class=post-date>2022-07-23</span>
 <span class=post-author>:: Nilstrieb</span>
-<span class=post-reading-time>:: 12 min read (2367 words)</span></div><span class=post-tags>#<a href=/tags/rust/>rust</a>&nbsp;
+<span class=post-reading-time>:: 12 min read (2381 words)</span></div><span class=post-tags>#<a href=/tags/rust/>rust</a>&nbsp;
 #<a href=/tags/unsafe-code/>unsafe code</a>&nbsp;</span><div class=post-content><div><p>We have all used <code>Box&lt;T></code> before in our Rust code. It&rsquo;s a glorious type, with great ergonomics
 and flexibility. We can use it to put our values on the heap, but it can do even more
 than that!</p><div class=highlight><pre tabindex=0 style=color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4><code class=language-rust data-lang=rust><span style=display:flex><span><span style=color:#66d9ef>struct</span> <span style=color:#a6e22e>Fields</span> {
@ -118,7 +118,7 @@ don&rsquo;t think this can reasonable be changed.</p><h1 id=noalias-noslow>noali
 that can bring clear performance wins (for <code>noalias</code> on <code>&mut T</code>, those were measureable). So the only question remains:
 <strong>How much performance does <code>noalias</code> on <code>Box&lt;T></code> give us now, and how many potential performance improvements could we get in the
 future?</strong> For the latter, there is no simple answer. For the former, there is. <code>rustc</code> has <a href=https://github.com/rust-lang/rust/pull/99527><em>no</em> performance improvements</a>
-from being compiled with <code>noalias</code> on <code>Box&lt;T></code>.</p><p>I have also benchmarked a few crates from the ecosystem with and without noalias on box, and the <a href=https://gist.github.com/Nilstrieb/9a0751fb9fd1044a30ab55cef9a7d335>results</a>
+from being compiled with <code>noalias</code> on <code>Box&lt;T></code>, but this isn&rsquo;t really representative since rustc mostly uses arenas instead of box internally.</p><p>I have also benchmarked a few crates from the ecosystem with and without noalias on box, and the <a href=https://gist.github.com/Nilstrieb/9a0751fb9fd1044a30ab55cef9a7d335>results</a>
 were inconclusive. (At the time of writing, only regex-syntax, tokio, and syn have been benchmarked.) regex-syntax showed no changes. Tokio showed a few improvements without noalias
 which is very weird, so maybe the benchmarks aren&rsquo;t really good or something else was going on. And syn tended towards minor regressions without noalias, but the benchmarks had high
 jitter so no real conclusion can be reached from this either, at least in my eyes, but I don&rsquo;t have a lot of experience with benchmarks. Therefore, I would love for more people
--- a/posts/index.xml
+++ b/posts/index.xml
@ -153,7 +153,7 @@ don&amp;rsquo;t think this can reasonable be changed.&lt;/p>
 that can bring clear performance wins (for &lt;code>noalias&lt;/code> on &lt;code>&amp;amp;mut T&lt;/code>, those were measureable). So the only question remains:
 &lt;strong>How much performance does &lt;code>noalias&lt;/code> on &lt;code>Box&amp;lt;T&amp;gt;&lt;/code> give us now, and how many potential performance improvements could we get in the
 future?&lt;/strong> For the latter, there is no simple answer. For the former, there is. &lt;code>rustc&lt;/code> has &lt;a href="https://github.com/rust-lang/rust/pull/99527">&lt;em>no&lt;/em> performance improvements&lt;/a>
-from being compiled with &lt;code>noalias&lt;/code> on &lt;code>Box&amp;lt;T&amp;gt;&lt;/code>.&lt;/p>
+from being compiled with &lt;code>noalias&lt;/code> on &lt;code>Box&amp;lt;T&amp;gt;&lt;/code>, but this isn&amp;rsquo;t really representative since rustc mostly uses arenas instead of box internally.&lt;/p>
 &lt;p>I have also benchmarked a few crates from the ecosystem with and without noalias on box, and the &lt;a href="https://gist.github.com/Nilstrieb/9a0751fb9fd1044a30ab55cef9a7d335">results&lt;/a>
 were inconclusive. (At the time of writing, only regex-syntax, tokio, and syn have been benchmarked.) regex-syntax showed no changes. Tokio showed a few improvements without noalias
 which is very weird, so maybe the benchmarks aren&amp;rsquo;t really good or something else was going on. And syn tended towards minor regressions without noalias, but the benchmarks had high
--- a/tags/rust/index.xml
+++ b/tags/rust/index.xml
@ -153,7 +153,7 @@ don&amp;rsquo;t think this can reasonable be changed.&lt;/p>
 that can bring clear performance wins (for &lt;code>noalias&lt;/code> on &lt;code>&amp;amp;mut T&lt;/code>, those were measureable). So the only question remains:
 &lt;strong>How much performance does &lt;code>noalias&lt;/code> on &lt;code>Box&amp;lt;T&amp;gt;&lt;/code> give us now, and how many potential performance improvements could we get in the
 future?&lt;/strong> For the latter, there is no simple answer. For the former, there is. &lt;code>rustc&lt;/code> has &lt;a href="https://github.com/rust-lang/rust/pull/99527">&lt;em>no&lt;/em> performance improvements&lt;/a>
-from being compiled with &lt;code>noalias&lt;/code> on &lt;code>Box&amp;lt;T&amp;gt;&lt;/code>.&lt;/p>
+from being compiled with &lt;code>noalias&lt;/code> on &lt;code>Box&amp;lt;T&amp;gt;&lt;/code>, but this isn&amp;rsquo;t really representative since rustc mostly uses arenas instead of box internally.&lt;/p>
 &lt;p>I have also benchmarked a few crates from the ecosystem with and without noalias on box, and the &lt;a href="https://gist.github.com/Nilstrieb/9a0751fb9fd1044a30ab55cef9a7d335">results&lt;/a>
 were inconclusive. (At the time of writing, only regex-syntax, tokio, and syn have been benchmarked.) regex-syntax showed no changes. Tokio showed a few improvements without noalias
 which is very weird, so maybe the benchmarks aren&amp;rsquo;t really good or something else was going on. And syn tended towards minor regressions without noalias, but the benchmarks had high
--- a/tags/unsafe-code/index.xml
+++ b/tags/unsafe-code/index.xml
@ -153,7 +153,7 @@ don&amp;rsquo;t think this can reasonable be changed.&lt;/p>
 that can bring clear performance wins (for &lt;code>noalias&lt;/code> on &lt;code>&amp;amp;mut T&lt;/code>, those were measureable). So the only question remains:
 &lt;strong>How much performance does &lt;code>noalias&lt;/code> on &lt;code>Box&amp;lt;T&amp;gt;&lt;/code> give us now, and how many potential performance improvements could we get in the
 future?&lt;/strong> For the latter, there is no simple answer. For the former, there is. &lt;code>rustc&lt;/code> has &lt;a href="https://github.com/rust-lang/rust/pull/99527">&lt;em>no&lt;/em> performance improvements&lt;/a>
-from being compiled with &lt;code>noalias&lt;/code> on &lt;code>Box&amp;lt;T&amp;gt;&lt;/code>.&lt;/p>
+from being compiled with &lt;code>noalias&lt;/code> on &lt;code>Box&amp;lt;T&amp;gt;&lt;/code>, but this isn&amp;rsquo;t really representative since rustc mostly uses arenas instead of box internally.&lt;/p>
 &lt;p>I have also benchmarked a few crates from the ecosystem with and without noalias on box, and the &lt;a href="https://gist.github.com/Nilstrieb/9a0751fb9fd1044a30ab55cef9a7d335">results&lt;/a>
 were inconclusive. (At the time of writing, only regex-syntax, tokio, and syn have been benchmarked.) regex-syntax showed no changes. Tokio showed a few improvements without noalias
 which is very weird, so maybe the benchmarks aren&amp;rsquo;t really good or something else was going on. And syn tended towards minor regressions without noalias, but the benchmarks had high