Welcome!

Cloud Security Authors: XebiaLabs Blog, Mehdi Daoudi, Derek Weeks, Liz McMillan, ManageEngine IT Matters

Related Topics: Containers Expo Blog, Linux Containers, @DevOpsSummit

Containers Expo Blog: Blog Feed Post

The Speed Index | @DevOpsSummit @Catchpoint #DevOps #WebPerf #DX #AI

There’s a lot of buzz around the speed index metric, but what exactly is this metric and how is it calculated?

Understanding Speed Index
By Moiz Khan

There’s a lot of buzz around the speed index metric, but what exactly is this metric and how is it calculated? Even more so, why do we need a new metric when there are so many already on the plate? This article gives you detailed answers to these questions.

What is speed index?
User expectations have changed drastically, webpages are expected to load faster with all elements rendering as soon as possible; user frustration increases if the visual content of the page is slow to load.

There are several metrics used to measure user experience, but do these give us a clear enough picture? Not really. For example, render start indicates when the page started painting, but this could mean it loaded a white background, a random object, or just a dot on the page; the user, however, may still be looking at a blank page. The document complete metric, which flags the onLoad event, may not be important from an end user’s perspective as it considers below-the-fold requests as well; there could be instances where the Document complete is triggered even when the page is blank.

Speed Index is an abstract score that was introduced to overcome the limitations of the current set of metrics. It measures user experience and unlike render start or document complete, it is not a timing metric, therefore the smaller the score, the better it is. Speed index takes into account the visual completeness of the page above-the-fold. It does a much better job of measuring the perceived performance of a page, but does this mean other metrics are irrelevant? This is debatable. Instead, the choice of a metric depends on the scenario and the nature of the website being analyzed.

How relevant is speed index?
Speed index will let you know if the visible content is loading quickly or not. The lower the score, the better is the user experience, and vice versa. The speed index score indicates whether you need to optimize your page or not. To maintain a good score, there are two critical aspects that you should look at: optimizing content efficiency and optimizing the critical rendering path.

Web applications continue to grow in terms of functionality, scope, and usability; hundreds of resources make up these applications and fetching each resource adds to the page load time. Maintaining performance is possible only when the resources and content that make up the page are optimized. Speed index plays a critical role in monitoring the performance of visible content.

How is it calculated?
Speed index lets you measure how quickly a page’s content is visible. However, it can be a little tricky to understand what it means and what factors contribute to the score.

Speed index uses film strips to calculate the score, each frame is scored for visual completeness above the fold – the score is 0% for a blank screen and 100% for a visually complete screen. The score for each frame is calculated using this formula:

interval time*(1 – visual complete %/100)

The process is repeated for every frame and the cumulative of all the scores gives you the speed index of that page.

Let’s take an example:

Adding all of the scores gives the speed index score:

500 + 450 + 350 + 200 + 50 = 1550

Here is another example:

Let’s add up the score:

500 + 500 + 475 + 400 + 350 = 2225

From a performance point of view, the lower the score the better it is. There is no defined benchmark for speed index, however, a score of <1000 is considered good. User experience is better if above-the-fold content is displayed faster, and this is what speed index determines.

Measuring speed index using Catchpoint
To check speed index, you will need to enable the “Capture Filmstrip” option under Advanced Settings of a test. It is displayed along with other metrics in the charts, and you can also view it in the waterfall graphs. Here are a few examples that illustrate how pages that load the visual content faster have a better speed index score.

Example 1:

In the above example, the page has a good speed index score of 1260. If you look at the film strip, the interval is of 500ms, and from the second frame the visual content is visible, which is about 1 second. Frame three has almost all the content loaded. From a user’s point of view, we have engaged them from the very first second due to the fact that the page is optimized.

Example 2:

In the above image, the visual is visible in the third frame. The first two frames are blank, which is why the speed index score of 1741 is higher than the first example. The user views content at 1.6 seconds, unlike the first example where the user viewed the content within a second.

Example 3:

Based on the final example above, we are able to understand what is happening. The first two frames are blank and in the third frame visual content starts to load. However, the completeness is less compared to the other two images in the same frame. The visual content continues to load in the fourth frame, but it’s not complete until the fifth frame. This means that the user needs to wait for 1.6 seconds to see something on the page, and another 2.8 seconds to view the complete visual content.

In all of the examples, the render start is triggered before the user views anything on the page. In the second example, the render start happens at 1195ms and the visible content starts to load at 1604ms. In the third example, the render start happens at 1296ms and the visible content starts to load at 1597ms. This is the uniqueness of speed index. With a highly unoptimized website, the difference could be extremely high, with render start happening quickly but the visible content loads quite late. You need these insights to optimize your websites.

Limitations of Speed Index
When running transaction tests for dynamic sites or single page applications that use ajax, the score is always good in the steps that follow once the page is opened. This is because the page does not refresh after it is loaded. Pages featuring carousels that rotate automatically may be penalized because they continue to change even after the page load is completed.

Summary
Speed index indicates the visual completeness of the page; however, it does not indicate if the content was critical or non-critical for the user. As such, it should not be a replacement for other metrics and should be considered a rather useful and much-needed addition to the list of metrics. You will still need to look at render start and document complete to understand the overall performance. Speed index gives you a different perspective of the user experience that your site delivers.

The post Understanding Speed Index appeared first on Catchpoint's Blog - Web Performance Monitoring.

More Stories By Mehdi Daoudi

Catchpoint radically transforms the way businesses manage, monitor, and test the performance of online applications. Truly understand and improve user experience with clear visibility into complex, distributed online systems.

Founded in 2008 by four DoubleClick / Google executives with a passion for speed, reliability and overall better online experiences, Catchpoint has now become the most innovative provider of web performance testing and monitoring solutions. We are a team with expertise in designing, building, operating, scaling and monitoring highly transactional Internet services used by thousands of companies and impacting the experience of millions of users. Catchpoint is funded by top-tier venture capital firm, Battery Ventures, which has invested in category leaders such as Akamai, Omniture (Adobe Systems), Optimizely, Tealium, BazaarVoice, Marketo and many more.

@ThingsExpo Stories
SYS-CON Events announced today that T-Mobile will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. As America's Un-carrier, T-Mobile US, Inc., is redefining the way consumers and businesses buy wireless services through leading product and service innovation. The Company's advanced nationwide 4G LTE network delivers outstanding wireless experiences to 67.4 million customers who are unwilling to compromise on ...
With major technology companies and startups seriously embracing Cloud strategies, now is the perfect time to attend @CloudExpo | @ThingsExpo, June 6-8, 2017, at the Javits Center in New York City, NY and October 31 - November 2, 2017, Santa Clara Convention Center, CA. Learn what is going on, contribute to the discussions, and ensure that your enterprise is on the right path to Digital Transformation.
20th Cloud Expo, taking place June 6-8, 2017, at the Javits Center in New York City, NY, will feature technical sessions from a rock star conference faculty and the leading industry players in the world. Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud strategy.
Data is an unusual currency; it is not restricted by the same transactional limitations as money or people. In fact, the more that you leverage your data across multiple business use cases, the more valuable it becomes to the organization. And the same can be said about the organization’s analytics. In his session at 19th Cloud Expo, Bill Schmarzo, CTO for the Big Data Practice at Dell EMC, introduced a methodology for capturing, enriching and sharing data (and analytics) across the organization...
Five years ago development was seen as a dead-end career, now it’s anything but – with an explosion in mobile and IoT initiatives increasing the demand for skilled engineers. But apart from having a ready supply of great coders, what constitutes true ‘DevOps Royalty’? It’ll be the ability to craft resilient architectures, supportability, security everywhere across the software lifecycle. In his keynote at @DevOpsSummit at 20th Cloud Expo, Jeffrey Scheaffer, GM and SVP, Continuous Delivery Busine...
With major technology companies and startups seriously embracing IoT strategies, now is the perfect time to attend @ThingsExpo 2016 in New York. Learn what is going on, contribute to the discussions, and ensure that your enterprise is as "IoT-Ready" as it can be! Internet of @ThingsExpo, taking place June 6-8, 2017, at the Javits Center in New York City, New York, is co-located with 20th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry p...
SYS-CON Events announced today that Juniper Networks (NYSE: JNPR), an industry leader in automated, scalable and secure networks, will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Juniper Networks challenges the status quo with products, solutions and services that transform the economics of networking. The company co-innovates with customers and partners to deliver automated, scalable and secure network...
New competitors, disruptive technologies, and growing expectations are pushing every business to both adopt and deliver new digital services. This ‘Digital Transformation’ demands rapid delivery and continuous iteration of new competitive services via multiple channels, which in turn demands new service delivery techniques – including DevOps. In this power panel at @DevOpsSummit 20th Cloud Expo, moderated by DevOps Conference Co-Chair Andi Mann, panelists will examine how DevOps helps to meet th...
SYS-CON Events announced today that Hitachi, the leading provider the Internet of Things and Digital Transformation, will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Hitachi Data Systems, a wholly owned subsidiary of Hitachi, Ltd., offers an integrated portfolio of services and solutions that enable digital transformation through enhanced data management, governance, mobility and analytics. We help globa...
@GonzalezCarmen has been ranked the Number One Influencer and @ThingsExpo has been named the Number One Brand in the “M2M 2016: Top 100 Influencers and Brands” by Analytic. Onalytica analyzed tweets over the last 6 months mentioning the keywords M2M OR “Machine to Machine.” They then identified the top 100 most influential brands and individuals leading the discussion on Twitter.
SYS-CON Events announced today that Hitachi, the leading provider the Internet of Things and Digital Transformation, will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Hitachi Data Systems, a wholly owned subsidiary of Hitachi, Ltd., offers an integrated portfolio of services and solutions that enable digital transformation through enhanced data management, governance, mobility and analytics. We help globa...
Most technology leaders, contemporary and from the hardware era, are reshaping their businesses to do software in the hope of capturing value in IoT. Although IoT is relatively new in the market, it has already gone through many promotional terms such as IoE, IoX, SDX, Edge/Fog, Mist Compute, etc. Ultimately, irrespective of the name, it is about deriving value from independent software assets participating in an ecosystem as one comprehensive solution.
The explosion of new web/cloud/IoT-based applications and the data they generate are transforming our world right before our eyes. In this rush to adopt these new technologies, organizations are often ignoring fundamental questions concerning who owns the data and failing to ask for permission to conduct invasive surveillance of their customers. Organizations that are not transparent about how their systems gather data telemetry without offering shared data ownership risk product rejection, regu...
NHK, Japan Broadcasting, will feature the upcoming @ThingsExpo Silicon Valley in a special 'Internet of Things' and smart technology documentary that will be filmed on the expo floor between November 3 to 5, 2015, in Santa Clara. NHK is the sole public TV network in Japan equivalent to the BBC in the UK and the largest in Asia with many award-winning science and technology programs. Japanese TV is producing a documentary about IoT and Smart technology and will be covering @ThingsExpo Silicon Val...
SYS-CON Events announced today that SoftLayer, an IBM Company, has been named “Gold Sponsor” of SYS-CON's 18th Cloud Expo, which will take place on June 7-9, 2016, at the Javits Center in New York, New York. SoftLayer, an IBM Company, provides cloud infrastructure as a service from a growing number of data centers and network points of presence around the world. SoftLayer’s customers range from Web startups to global enterprises.
Bert Loomis was a visionary. This general session will highlight how Bert Loomis and people like him inspire us to build great things with small inventions. In their general session at 19th Cloud Expo, Harold Hannon, Architect at IBM Bluemix, and Michael O'Neill, Strategic Business Development at Nvidia, discussed the accelerating pace of AI development and how IBM Cloud and NVIDIA are partnering to bring AI capabilities to "every day," on-demand. They also reviewed two "free infrastructure" pr...
SYS-CON Events announced today that Super Micro Computer, Inc., a global leader in compute, storage and networking technologies, will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Supermicro (NASDAQ: SMCI), the leading innovator in high-performance, high-efficiency server technology, is a premier provider of advanced server Building Block Solutions® for Data Center, Cloud Computing, Enterprise IT, Hadoop/...
Judith Hurwitz is president and CEO of Hurwitz & Associates, a Needham, Mass., research and consulting firm focused on emerging technology, including big data, cognitive computing and governance. She is co-author of the book Cognitive Computing and Big Data Analytics, published in 2015. Her Cloud Expo session, "What Is the Business Imperative for Cognitive Computing?" is scheduled for Wednesday, June 8, at 8:40 a.m. In it, she puts cognitive computing into perspective with its value to the busin...
NHK, Japan Broadcasting, will feature the upcoming @ThingsExpo Silicon Valley in a special 'Internet of Things' and smart technology documentary that will be filmed on the expo floor between November 3 to 5, 2015, in Santa Clara. NHK is the sole public TV network in Japan equivalent to the BBC in the UK and the largest in Asia with many award-winning science and technology programs. Japanese TV is producing a documentary about IoT and Smart technology and will be covering @ThingsExpo Silicon Val...
SYS-CON Events announced today that CollabNet, a global leader in enterprise software development, release automation and DevOps solutions, will be a Bronze Sponsor of SYS-CON's 20th International Cloud Expo®, taking place from June 6-8, 2017, at the Javits Center in New York City, NY. CollabNet offers a broad range of solutions with the mission of helping modern organizations deliver quality software at speed. The company’s latest innovation, the DevOps Lifecycle Manager (DLM), supports Value S...