velocity_Velocity在线会议2011年3月

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velocity

Very rough notes from the event that just ended a few minutes ago

几分钟前结束的活动中的非常粗糙的注释

======== 1 ========

Tony Gentilcore (google) and Anderson Quach (MSFT) talked about the W3C working group and the specs for measuring performance:

Tony Gentilcore(google)和Anderson Quach(MSFT)讨论了W3C工作组以及衡量性能的规范：

Navigation timing spec - HTML document: DNS, handshakes, load events
导航时序规范-HTML文档：DNS，握手，加载事件
Resource timing - how long JS, CSS, audio, video... take
资源计时-JS，CSS，音频，视频...需要多长时间
User timing - interactions, such as clicking a link
用户计时-交互，例如单击链接

Challenges: user security, privacy. Small overhead for browsers. Useful actionable data out.

挑战：用户安全，隐私。浏览器的开销很小。有用的可行数据。

Navigation timing:

导航时间：

window.performance - IE9 has no vendor prefix
window.performance -IE9没有供应商前缀
otherwise window.webkitPerformance
否则window.webkitPerformance
FF4 probably shipping it too
FF4可能也发货了

Properties:

特性：

window.performance.timing
  .domainLookup
  .connect
  .domContentLoaded
  .loadEvent
  ....etc

Specs: http://test.w3.org/webperf/specs/NavigationTiming/

规格： http ： //test.w3.org/webperf/specs/NavigationTiming/

Resource Timing spec - upcoming

资源时序规范-即将推出

foreach resource 
  redirect
  fetchStart
  fetchEnd
  ...

User Timing - upcoming

用户计时-即将推出

  mark('pagelet')
  mark('something-else')
  ...
  
  >>> getMarks();
  {
    'pagelet': 123456767
  }

Stretch goals:

伸展目标：

painting times
绘画时间
CPUs
中央处理器
visibility (is the page in a background tab)
可见性(页面在背景选项卡中)
allow real yealding setTimeout(0)
允许真正的预设置setTimeout(0)
don't animate faster than the browser paints
动画制作的速度不超过浏览器绘制的速度

mailto: public-web-perf@w3c.org

mailto：public-web-perf@w3c.org

======== 2 ========

Above the Fold Time: Measuring Web Page Performance Visually Speaker: Jake Brutlag Help from: Zoe Abrams, Pat Meenan (webpagetest) Google

折时之上：直观地测量网页性能演讲者：Jake Brutlag帮助来自：Zoe Abrams，Pat Meenan(webpagetest)Google

What the user perception of page load timing is.

用户对页面加载时间的看法是什么。

AFT (Above the Fold Timing) algo AFT: When content above the fold stops changing and reaches its final state

AFT(高于折叠时间)算法AFT：当折叠上方的内容停止变化并达到最终状态时

Integrated in WebPageTest.org

集成在WebPageTest.org中

Motivation

动机

AFT more representative than DOMContentLoaded or onload
AFT比DOMContentLoaded或onload更具代表性
onload - different in IE and FF, e.g. async scripts block onload or not
onload -IE和FF中的不同，例如异步脚本是否阻止onload

Method:

方法：

video capture
视频截取
AFT cutoff time - upper bound, e.g. 45 sec for DSL
AFT截止时间-上限，例如DSL为45秒
split pixels into static and dymanic (ads)
将像素分为静态和动态(广告)
AFT = latest change of a static pixel
AFT =静态像素的最新变化

Magic number - 5 determined empirically static pixels are those that change less than 5 times

幻数-5个根据经验确定的静态像素是那些变化小于5倍的像素

Application - validate other metrics, cross-browser, visual Limitation - lab only

应用程序-验证其他指标，跨浏览器，可视限制-仅实验室

{I ran webpagetest.org on facebook.com with AFT on. The results are very close to onload, as expected. It's a simple page. Results: http://www.webpagetest.org/result/110315_P9_5MDJ/ }

{我在启用AFT的情况下在facebook.com上运行了webpagetest.org。正如预期的那样，结果非常接近onload。这是一个简单的页面。结果：http://www.webpagetest.org/result/110315_P9_5MDJ/}

== break ==

==休息==

Note from the sponsor StrangeLoop: a downloadable "State of the Union" A study of top 2000 Alexa retail sites. Findings:

赞助商StrangeLoop的注释：可下载的“国际联盟”状态研究Alexa排名前2000的零售网站。发现：

11.2 sec onload avg
平均11.2秒加载时间
top 100 sites slower than the lower ranked
前100个网站的排名低于排名较低的网站
those using CDNs are not faster
那些使用CDN的人并不快
failed to implement the basics - YSlow stuff
未能实现基础知识-YSlow的东西

======== 3 ========

Next-gen YSlow Betty Tso and Marcel Duran, Yahoo!

下一代YSlow Betty Tso和Marcel Duran，雅虎！

YSlow for Chrome last week Not as accurate as Firefox cause headers, timing come from: 1. Crawl DOM 2. x-domain requests

上周针对Chrome的YSlow不如Firefox原因标头准确，计时来自：1.抓取DOM 2. x域请求

Announcing YSlow bookmarklet version for mobile and all other browsers to be released early april YSlow now on Git?

宣布在移动版和所有其他浏览器上使用的YSlow书签版本将在Git上于YSlow于4月初发布吗？

Lots coming up, e.g:

大量涌现，例如：

Multi-language support
多国语言支持
HAR-to-YSlow
从低到高
YSlow export to JDrop
YSlow导出到JDrop

Bookmarket works like: 1. crawl DOM 2. Use YQL to get headers

Bookmarket的工作方式如下：1.爬网DOM 2.使用YQL获取标题

     SELECT * FROM data.headers WHERE
      url IN ('http://...', 'http://...')

======== 4 ========

Visibility into Mobile Performance Steve Souders, Google

Google对移动性能的了解Steve Souders，Google

Demo #1: http://blaze.io/mobile/ WebPageTest.org framework connected to iPhone and Android apps Mobile waterfalls Demo #2: pcapperf 1. setup wifi hotspot on a pc/mac 2. tcpdump to capture .pcap file 3. upload .pcap to http://pcapperf.appspot.com app 4. observe waterfall via pcap2har and harviewer 5. run pagespeed on the har Demo #3: JDrop http://jdrop.org Upload JSON so you can run something on mobile and view/analyze results in desktop's large screen Works with the bookmarklet tools part of Steve's package of mobile meta-tool

演示1：连接到iPhone和Android应用程序的http://blaze.io/mobile/ WebPageTest.org框架移动瀑布演示2： pcapperf 1.在pc / mac上设置wifi热点2. tcpdump捕获.pcap文件3 。将.pcap上传到http://pcapperf.appspot.com应用程序4.通过pcap2har和harviewer观察瀑布5.在har上运行pagespeed演示＃3：JDrop http://jdrop.org上传JSON，以便您可以在移动和查看/分析可在桌面大屏幕上显示结果与Steve移动元工具包中的小书签工具一起使用

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