| <!DOCTYPE html><html><head><meta charset="utf-8" /><meta content="IE=edge" http-equiv="X-UA-Compatible" /><meta content="width=device-width, initial-scale=1, maximum-scale=2.0, user-scalable=yes, minimal-ui=yes" name="viewport" /><title>facil.io - Fast Concurrent Memory Allocator</title><meta content="facil.io - Fast Concurrent Memory Allocator" name="description" /><link href="https://fonts.googleapis.com/css?family=Montserrat|Quicksand|Karla" rel="stylesheet" type="text/css" /><script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.4/jquery.min.js"></script><link href="/assets/styles/main.css" rel="stylesheet" type="text/css" /><script type="application/ld+json">{"@context":"http://schema.org","@type":"WebSite","url":"http://facil.io","name":"facil.io","description":"facil.io - a light web application framework in C, with support for HTTP, WebSockets and Pub/Sub out of the box.","keywords":"C, web, framework, websockets, websocket, realtime, real-time, easy","image":"http://facil.io/website/logo/facil-io.svg","author":[{"@type":"Person","name":"Bo (Myst)","url":"http://stackoverflow.com/users/4025095/myst","email":"bo(at)facil.io"}],"sourceOrganization":{"@context":"http://schema.org","@type":"Organization","name":"Plezi","url":"http://facil.io","description":"facil.io - a light web application framework in C, with support for HTTP, WebSockets and Pub/Sub out of the box.","logo":"http://facil.io/website/logo/facil-io.svg","image":"http://facil.io/website/logo/facil-io.svg","email":"bo(at)facil.io","member":[{"@type":"Person","name":"Bo (Myst)","url":"http://stackoverflow.com/users/4025095/myst","email":"bo(at)facil.io"}]}}</script><meta content="facil.io" name="apple-mobile-web-app-title" /><meta content="facil.io - the C Web Application Framework" name="application-name" /><meta content="#b91d47" name="msapplication-TileColor" /><meta content="/mstile-144x144.png" name="msapplication-TileImage" /><meta content="#ffffff" name="theme-color" /></head><body><a href="/" id="logo"></a><input id="show_nav" type="checkbox" /><nav id="top_nav"><ul><li><a href="/0.7.x/index">Latest Docs</a></li><li><a href="https://github.com/boazsegev/facil.io" target="_blank">Source Code</a></li><li><a href="javascript: change_themes();" id="theme">Night Theme</a></li></ul></nav><input id="show_sidebar" type="checkbox" /><nav id="side_bar"><h2 id="version-0-6-x"><a href="/0.6.x/index">Version 0.6.x</a></h2> |
| |
| <ul> |
| <li><a href="/0.6.x/api">API Overview</a></li> |
| <li><a href="/0.6.x/modules">The Modules</a></li> |
| </ul> |
| |
| <h3 id="core-api"><a href="/0.6.x/facil">Core API</a></h3> |
| |
| <ul> |
| <li><a href="/0.6.x/defer">Event scheduling</a></li> |
| <li><a href="/0.6.x/evio">Low Level Polling</a></li> |
| <li><a href="/0.6.x/sock">Low Level Sockets</a></li> |
| <li><a href="/0.6.x/fio_mem">Memory Allocation</a></li> |
| </ul> |
| |
| <h3 id="extensions">Extensions</h3> |
| |
| <ul> |
| <li><a href="/0.6.x/http">HTTP</a></li> |
| <li><a href="/0.6.x/websockets">WebSockets</a></li> |
| <li><a href="/0.6.x/pubsub">Pub/Sub</a></li> |
| <li><a href="/0.6.x/fio_cli">CLI (command line)</a></li> |
| </ul> |
| |
| <h3 id="the-fiobj-types"><a href="/0.6.x/fiobj">The FIOBJ types</a></h3> |
| |
| <ul> |
| <li><a href="/0.6.x/fiobj_primitives">Primitives</a></li> |
| <li><a href="/0.6.x/fiobj_numbers">Numbers</a></li> |
| <li><a href="/0.6.x/fiobj_str">Strings</a></li> |
| <li><a href="/0.6.x/fiobj_ary">Array</a></li> |
| <li><a href="/0.6.x/fiobj_hash">HashMap</a></li> |
| <li><a href="/0.6.x/fiobj_json">JSON</a></li> |
| </ul> |
| |
| <h3 id="core-types"><a href="/0.6.x/types">Core Types</a></h3> |
| |
| <ul> |
| <li><a href="/0.6.x/fio_ary">C Arrays</a></li> |
| <li><a href="/0.6.x/fio_hashmap">C HashMap</a></li> |
| <li><a href="/0.6.x/fio_llist">Linked Lists</a></li> |
| </ul> |
| </nav><div id="md_container"><div class='toc'><ul> |
| <li> |
| <a href="#facil-io-fast-concurrent-memory-allocator">facil.io - Fast Concurrent Memory Allocator</a> |
| <ul> |
| <li> |
| <a href="#overview">Overview</a> |
| <ul> |
| <li> |
| <a href="#example">example</a> |
| </li> |
| </ul> |
| </li> |
| <li> |
| <a href="#constants">Constants</a> |
| </li> |
| <li> |
| <a href="#types">Types</a> |
| </li> |
| <li> |
| <a href="#functions">Functions</a> |
| </li> |
| <li> |
| <a href="#important-notes">Important Notes</a> |
| </li> |
| </ul> |
| </li> |
| </ul> |
| </div><h1 id="facil-io-fast-concurrent-memory-allocator">facil.io - Fast Concurrent Memory Allocator</h1> |
| |
| <p>The system's memory allocator is usually highly optimized and very performant. In fact, for most cases, it should probably be preferred.</p> |
| |
| <p>However, the system's memory allocator is optimized for generic unknown use-cases which means that sometimes a custom memory allocator will perform better for a subset of use-cases.</p> |
| |
| <p>facil.io includes a memory allocator that was optimized for small (less than a page) concurrent group allocations and deallocations (calling <code>malloc</code> a bunch of times and than calling <code>free</code> a bunch of times from many different threads) with minimal or no reallocations (minimal use of <code>realloc</code>).</p> |
| |
| <p>The <code>fio_mem.h</code> allocator will minimize overhead and lock contention, allowing for better concurrency.</p> |
| |
| <h2 id="overview">Overview</h2> |
| |
| <p>The <code>fio_mem.h</code> allocator is used the same way the system allocator is used, prefixing it's functions with <code>fio_</code> - so the <code>fio_malloc</code>, <code>fio_free</code>, <code>fio_realloc</code> and <code>fio_calloc</code> take the same parameters as <code>malloc</code>, <code>free</code>, <code>realloc</code> and <code>calloc</code> respectively.</p> |
| |
| <p>Allocated memory is always zeroed out and aligned on a 16 byte boundary. When possible, consecutive calls to <code>fio_malloc</code> will return with a close physical memory address to the previous allocation, resulting in improved locality.</p> |
| |
| <p>The memory allocator assumes multiple concurrent allocation/deallocation, short life spans (memory is freed shortly after it was allocated) and small allocations (<code>fio_realloc</code> almost always copies data).</p> |
| |
| <p>These assumptions allow the allocator to ignore fragmentation within a memory "block", waiting for the whole "block" to be freed before it's memory is recycled.</p> |
| |
| <p>This allocator should NOT be used for objects with a long life-span, because even a single persistent object will prevent the re-use of the whole memory block (128Kb by default) from which it was allocated.</p> |
| |
| <p>This documentation is incomplete. I would love your help to finish it up. Until that time, please read the documentation in <a href="https://github.com/boazsegev/facil.io/blob/master/lib/facil/core/types/fiobj/fio_mem.h">the <code>fio_mem.h</code> header file</a>.</p> |
| |
| <h3 id="example">example</h3> |
| |
| <h2 id="constants">Constants</h2> |
| |
| <h2 id="types">Types</h2> |
| |
| <h2 id="functions">Functions</h2> |
| |
| <h2 id="important-notes">Important Notes</h2> |
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