The Truth About Your Web App's Performance

The Truth About Your Web App's Performance

From JSConf US 2014, where I announced the release of Surf-N-Perf, our micro-library for gathering web page performance data (https://github.com/Comcast/Surf-N-Perf)

Video Available at http://youtu.be/0dBU6leL0Og

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John Riviello

May 28, 2014
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Transcript

  1. 3.

    Frontend Performance Data 1.  What do existing tools provide? 2. 

    What data do you care about? 3.  How do you gather that data? 4.  What do you do with the data? John Riviello – The Truth Behind Your Web App’s Performance 3
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    1. Existing Tools 2. The Data You Care About 3.

    Gathering the Data 4. Analyzing the Data
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    Real User Monitoring "yes, that's a rum filled coconut." (https://www.flickr.com/photos/bking/346334125)

    by Brandon King (https://www.flickr.com/photos/bking/) is licensed under CC BY-NC 2.0 (https://creativecommons.org/licenses/by-nc/2.0/) / Color adjusted from original
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    1. Existing Tools 2. The Data You Care About 3.

    Gathering the Data 4. Analyzing the Data
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    Real User Monitoring "yes, that's a rum filled coconut." (https://www.flickr.com/photos/bking/346334125)

    by Brandon King (https://www.flickr.com/photos/bking/) is licensed under CC BY-NC 2.0 (https://creativecommons.org/licenses/by-nc/2.0/) / Color adjusted from original
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    Frontend Performance Data – The Data You Care About John

    Riviello – The Truth Behind Your Web App’s Performance 29
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    Frontend Performance Data – The Data You Care About Example

    Factors That Impact Performance: John Riviello – The Truth Behind Your Web App’s Performance 30 •  User authentication state • “Type” of user •  Number of “items” returned •  SWF dependency
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    http://mashable.com/2014/01/31/gmail-slow/ John Riviello – The Truth Behind Your Web App’s

    Performance 32 “Gmail’s People Widget appears to be the cause of the sluggishness, which is, only affecting Gmail on the web Google says… This is noticeable when users open an email conversation with a large number of participants…”
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    1. Existing Tools 2. The Data You Care About 3.

    Gathering the Data 4. Analyzing the Data
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    Frontend Performance Data – Gathering the Data Marking Timestamps John

    Riviello – The Truth Behind Your Web App’s Performance 36 Back in the day: >  new  Date().getTime();        1399754123456   ECMAScript 5.1: >  Date.now();        1399754123456   Most modern browsers have a better option…      
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    Frontend Performance Data – Gathering the Data W3C High Resolution

    Time John Riviello – The Truth Behind Your Web App’s Performance 38 • DOMHighResTimeStamp is available via window.performance.now() • Provides the time with sub-millisecond accuracy • Measured relative to the navigationStart attribute of the PerformanceTiming interface • Not subject to system clock skew or adjustments (uses a monotonically increasing clock)
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    Frontend Performance Data – Gathering the Data W3C High Resolution

    Time – Sub-ms Example John Riviello – The Truth Behind Your Web App’s Performance 39 >  var  dateTest  =  function()  {              var  start  =  Date.now(),                      area  =  window.innerWidth*window.innerHeight;              return  Date.now()  -­‐  start;      };      dateTest();      0     >  var  highResTest  =  function()  {              var  start  =  window.performance.now(),                      area  =  window.innerWidth*window.innerHeight;              return  window.performance.now()  -­‐  start;      };      highResTest();      0.01200000406242907  
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    Frontend Performance Data – Gathering the Data W3C High Resolution

    Time – Monotonic Clock John Riviello – The Truth Behind Your Web App’s Performance 40 Why do we care? “Most systems run a daemon which regularly synchronizes the time. It is common for the clock to be tweaked a few milliseconds every 15-20 minutes. At that rate about 1% of 10 second intervals measured would be inaccurate.” Source: Tony Gentilcore http://gent.ilcore.com/2012/06/better-timer-for-javascript.html
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    1. Existing Tools 2. The Data You Care About 3.

    Gathering the Data 4. Analyzing the Data
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    Frontend Performance Data – Analyzing The Data John Riviello –

    The Truth Behind Your Web App’s Performance 53
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    Frontend Performance Data – Analyzing The Data John Riviello –

    The Truth Behind Your Web App’s Performance 56
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    Frontend Performance Data – Analyzing The Data John Riviello –

    The Truth Behind Your Web App’s Performance 57
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    Frontend Performance Data – Analyzing The Data John Riviello –

    The Truth Behind Your Web App’s Performance 58
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    Frontend Performance Data – Analyzing The Data John Riviello –

    The Truth Behind Your Web App’s Performance 59
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    Frontend Performance Data – Analyzing The Data John Riviello –

    The Truth Behind Your Web App’s Performance 60
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    Frontend Performance Data – Analyzing The Data John Riviello –

    The Truth Behind Your Web App’s Performance 61
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    Frontend Performance Data – Analyzing The Data John Riviello –

    The Truth Behind Your Web App’s Performance 62
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    Frontend Performance Data – Analyzing The Data John Riviello –

    The Truth Behind Your Web App’s Performance 63
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    Frontend Performance Data – Analyzing The Data John Riviello –

    The Truth Behind Your Web App’s Performance 64
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    Frontend Performance Data – Recap John Riviello – The Truth

    Behind Your Web App’s Performance 66 • Measure first—at the 99th percentile • Log Network Latency, Processing Time, and Full Webpage Request • Log major app-specific events with details • Leverage W3C Performance APIs For Further Info: Twitter: @JohnRiv GitHub: https://github.com/Comcast/Surf-N-Perf