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Meetup Performance
 

Meetup Performance

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    Meetup Performance Meetup Performance Presentation Transcript

    • Meetup PerformanceGreg Whalin, CTO Meetup (@gwhalin), Justin Cataldo, Lead UI Engineer (@jcataldo), Will Howard, Lead UI Engineer
    • MeetupPlatform for local groupsMission is MEME (Meetup Everywhere About Most Everything)~6.2m members~70k Groups~500k group joins every month~5 million Meetups have happened~53 million RSVPs
    • General Architecture and Back- end Performance (just a tiny bit - this could and should be another presentation)
    • DataMySQL (any RDBMs store) biggest pain replication use InnoDB! smart indexing (take advantage of clustered indexes) server side conn pools and short timeouts on connections smart about fs choice on Linux (we use XFS after benchmarking)Hardware - relatively expensive boxes multi-core (8 or 16) Opteron lots of ram (32/64GB) fast drives (lots of spindles, RAID10)Cache, cache, cache! innodb buffer cache memcache local app server memoryShrink data when possible archive unused data custom serialization when serializing data partitioning/sharding
    • Storage Over half a million photos uploaded to Meetup every month Scaled and processed into 4 different sizes (plus original)
    • Storage solutions Options for growth include NAS, SAN, or something else NAS and SAN are single point of failure and possibly $$$ Only postpones problem
    • MogileFS developed by Brand Fitzpatrick (i.e. Memcached) OSS distributed filesystem (built in Perl) any hard drive on network can easily be added to cluster scales easily and cheaply
    • Much much much more going on but...
    • UI Performance(much of our focus here)
    • Why does performance matter?
    • Why does performance matter? Slow site
    • Why does performance matter? Slow site Bad User Experience
    • Why does performance matter? Slow site Bad User Experience Drop in Member Activity
    • Why focus on front end performance? Back end only accounts for 10-15% of the response time Less time and resources Costs less http://developer.yahoo.net/blog/archives/2007/03/high_performanc.html
    • Case Study: Event Details
    • Event Details: Load Time Load time = 6.321swww.webpagetest.org
    • Event Details: Requests Lots of javascript being loaded
    • How do we improve performance?
    • 3 Steps to improving performance1. Externalize script2. Move scripts to the bottom of the page3. Reduce requests
    • 3 Steps to improving performance1. Externalize script2. Move scripts to the bottom of the page3. Reduce requests
    • Why externalize scripts Prevents blocking Inline scripts prevent asynchronous downloads Downloads must wait for the script to be executed Caching Inline JavaScript is downloaded every time External scripts are cached by the browser Reduced overall page size Reusable Can use the same code somewhere else on the site easily
    • Pull out inline script<script type="text/javascript"> >if(typeof Meetup.EventDetails == undefined) Meetup.EventDetails = {};(function(){ EventDetails.js var self = Meetup.EventDetails;...})();</script>
    • 3 Steps to improving performance1. Externalize script2. Move scripts to the bottom of the page3. Reduce requests
    • Web:script Custom tag built in house Moves inline and external script to the bottom of the page Allows UI engineers to not have to worry about where they place scripts Compresses inline script using YUICompressor/***** Load External Script *****/<web:script src="/script/Meetup/packed/EventDetails.js" />/***** Load Inline Script *****/<web:script> Meetup.Copy.noMembersMarkedAttended = "<trn:message key="event.attendance.noMembersMarkedAttended">Nomembers have been marked attended</trn:message>"; Meetup.Copy.noMembersMarkedAttendedDynam = <trn:message key="event.attendance.noMembersMarkedAttendedDynam"><trn:param name="GROUPING">__GROUPING__</trn:param>No members in"{GROUPING}" have been marked attended</trn:message>; Meetup.Copy.noMembersMarkedAbsent = "<trn:message key="event.attendance.noMembersMarkedAbsent">Nomembers have been marked absent</trn:message>";</web:script>
    • 3 Steps to improving performance1. Externalize script2. Move scripts to the bottom of the page3. Reduce requests
    • Reduce Requests Concatenate as much as possible Load only what we need upfront
    • Concatenation using Sprockets Sprockets (www.getsprockets.com) Created by 37Signals Ruby library that preprocesses and concatenates JavaScript files Baked into our build process
    • Concatenation using Sprockets (cont.)EventDetails.jsCommentDeleteConfirm.jsBubbleTips.jsPlacesManager.jsMaxCharactersEnforcer.js > EventDetails.js
    • Using Sprockets/******* Sprockets Directives *******///= require <CommentDeleteConfirm>//= require <DomDeco/BubbleTips>//= require <DomDeco/PlacesManager>//= require <DomDeco/MaxCharactersEnforcer>/******* Begin Event Details Code *******/if(typeof(Meetup.EventDetails) == undefined) Meetup.EventDetails = {};(function(){ var self = Meetup.EventDetails;...........})();/******* Build Process *******/<exec executable="sprocketize" failonerror="true" output="${image.dir}/script/Meetup/packed/EventDetails.js"> <arg value="-I"/> <arg path="${image.dir}/script/Meetup/"/> <arg path="${image.dir}/script/Meetup/EventDetails.js"/></exec>
    • Lazy Loading Defer loading of javascript files until they are needed Reduces the initial upfront requests Helps reduce blocking by downloading files asynchronously Precaching
    • Lazy Loading: How it worksInserts scripts into the head dynamically var scriptNode = function(src) { return createDOM("script", { "type": "text/javascript", "src": src }); } var load = function(id, src, n) { var script = scriptNode(url); head.appendChild(script); script.onload = script.onreadystatechange = function() { if (!this.readyState || this.readyState == "loaded" || this.readyState == "complete") { script.onload = script.onreadystatechange = null; } } }Meetup.Script.include("http://static2.meetupstatic.com/script/Meetup/DomDeco/LinkDecorator.js",callback);
    • Did it make a difference?
    • Reduced requests Javascript requests cut by 50%
    • Event DetailsPage Load AfterOld Load Time = 6.321sNew Load time = 4.643s
    • Event DetailsPage Load AfterOld Load Time = 6.321sNew Load time = 4.643s Load time decreased by 27%!
    • But thats not all
    • Execute early Execute when the dom is ready
    • Execute early: DOMReadyLibraries that have a DOM ready solution: jQuery YUI Prototype Pretty much every modern JS library (not MochiKit) Meetup uses MochiKit, so we rolled our own.
    • Execute early: DOMReadyAnd by rolled our own, I mean were using the DeanEdwards/Matthias Miller/John Resig implementation.http://dean.edwards.name/weblog/2006/06/again/#comment5338With a few changes. Meetup.DOMReady.ready(function(){ Meetup.EventDetails.init(); if(Meetup.EventDetails.isCanceled != 4 && Meetup.EventDetails.rsvp != 0){ deletePopup = new Meetup.CommentDeleteConfirm(); deletePopup.pagerOffsetFieldName = "p_commentsList"; deletePopup._decorate(); } });
    • Execute early: Even earlierDo you need to wait for the DOM to be ready?If you arent manipulating the DOM, theres no reason towait until its ready.
    • Automated Image OptimizationUsing smush.ithttp://developer.yahoo.com/yslow/smushit/Smusher Ruby gemhttp://github.com/grosser/smusher (gem install smusher)BASH script that watches our image directories forchanges and executes smusher. ./filescan.sh /usr/local/meetup/static/img/ smusher -q @ jpg,png&
    • Event DelegationRun less JavaScript up front
    • Event DelegationBut first, a little bit about event bubbling... From: http://www.quirksmode.org/js/events_order.html
    • Event DelegationPros Cons Does not work well with nested elements Much faster on load (not Doesnt work with all events connecting DOM elements) Slight performance hit with execution No need to disconnect / reconnect with AJAX calls Fewer memory leaks A lot of JS libraries already have plug-ins for event delegation (jQuery, YUI, prototype). But, its pretty easy to write your own (we did).
    • Event Delegation: Meetup.Dispatcher <div id="C_page"> ... <span class="meetup-topic"><a class="topic-id-7029 topic-link J_onClick topic-info-hover" href=" http://javascript.meetup.com/cities/us/ny/brooklyn/">JavaScript</a></span> ... </div> var mdp = Meetup.Dispatcher.init("C_page", "onmouseover"); mdp.registerFunc("topic-info-hover", Meetup.UI.InfoHover.mouseOver); Meetup.UI.infoHover.mouseOver = function(e) { topicId = _getTopicId(e.target()); if (!topicId || topicId == "") return; _primeCache(topicId); var activeEl = _getActiveEl(e.target()); var pos = getElementPosition(activeEl); ... }
    • Event Delegation: Meetup.Dispatcher
    • Event Delegation: Meetup.Dispatcher <div id="C_page"> ... <span class="meetup-topic"><a class="topic-id-7029 topic-link J_onClick topic-info-hover" href=" http://javascript.meetup.com/cities/us/ny/brooklyn/">JavaScript</a></span> ... </div> // Inits a new instance of dispatcher // Connects a mouseover event to the parent container "C_page" var mdp = Meetup.Dispatcher.init("C_page", "onmouseover"); // Calls Meetup.UI.infoHover.mouseOver() when target element has "topic-info-hover" class. mdp.registerFunc("topic-info-hover", Meetup.UI.InfoHover.mouseOver); Meetup.UI.infoHover.mouseOver = function(e) { topicId = _getTopicId(e.target()); if (!topicId || topicId == "") return; _primeCache(topicId); var activeEl = _getActiveEl(e.target()); var pos = getElementPosition(activeEl); ... }
    • Speeding up DOM crawling with Sizzle sizzlejs.com Internet Explorer 7 MochiKit: 6623.94ms Sizzle: 306.03ms Firefox 3.5 MochiKit: 210.524ms Sizzle: 111.553ms
    • Where do we go from here? More concatenation and lazy loading where it makes sense Defer image loading where it makes sense Reduce DOM elements Reduce CSS and improved selector efficiency and more
    • Deployment and Serving As it pertains to css/html/js
    • LaunchesLaunch multiple times a day (sometimes)Need launches to be quick / no downtimeOptimize static resources only at deploy time and only ifmodified
    • Deployment of static contentSprockets (reduce requests)YUICompressor for js (local mod to speed up optimizingmultiple files)Pre-compress css and jspSet cache-control to be fresh for over a year (indefinite)All links on site generate programatically and versioned
    • Link generation Custom JSTL page function http vs https domain sharding and cookie free domain content versioning<link rel="stylesheet" href="${mfn:staticUrl( "/style/meetup.css", state.context.isSecure )}" type="text/css" /><img src="${mfn:imgUrl( /img/noPhoto_50.gif, state.context.isSecure )}" alt=""class="noPhoto" /><link rel="stylesheet" href="http://static1.meetupstatic.com/050991196173395491322880/style/meetup.css" type="text/css" /><img src="http://img1.meetupstatic.com/39194172310009655/img/noPhoto_50.gif" alt="" class="noPhoto"/>
    • Versioning static content MD5 checksum of contents of file Run w/ each launch Store versions in db tied to release mysql> select * from resource_version where filename = /style/base.css; | 394328 | /style/base.css | 39020083689267241 | 567 | | 398052 | /style/base.css | 8487620432388779772669 | 568 | | 401776 | /style/base.css | 357470606563045379 | 569 | | 405506 | /style/base.css | 3068234199748867 | 571 | | 409240 | /style/base.css | 024745310801291061590 | 572 | | 412974 | /style/base.css | 024745310801291061590 | 573 | | 416708 | /style/base.css | 09972542737049101325 | 574 |
    • Static content serving Served off CDN (reverse proxy) Anycast DNS for hostname resolution Origin servers running lighttpd Strip versioning from url using rewrite rules Cache set to 12 months out Compressexpire.url = ( "/" => "access plus 12 months")compress.cache-dir = "/var/cache/lighttpd/"compress.filetype = ("text/plain", "text/html", "text/css", "application/x-javascript", "text/javascript")url.rewrite-once = ( "^/script/(.*/)?[0-9]+/(.+).js$" => "/script/$1$2.js", "^/style/(.*/)?[0-9]+/(.+).css$" => "/style/$1$2.css", "^/img/(.*/)?[0-9]+/(.+).(gif|png|jpg)$" => "/img/$1$2.$3", "^/d+/script/(.+).js" => "/script/$1.js", "^/d+/style/(.+).css" => "/style/$1.css", "^/d+/img/(.+).(gif|jpg|png)" => "/img/$1.$2", "^/photos/(([^/]+)/.+/(.+).jpeg)(?:?.*)?$" => "/cgi-bin/photos.fcgi?type=$2&key=$3", "^/photos/([^/]+)/([^/]+).jpeg(?:?.*)?$" => "/cgi-bin/photos.fcgi?type=$1&key=$2", "^/file.*" => "/")
    • Questions?Also, we need help! Hiring for: Linux Systems Administrator Software Engineers UI Engineers QA Engineers Community Specialist PR Renegade Sponsorship Sales Account Coordinatorhttp://www.meetup.com/jobs/