Skip to content

Commit f425694

Browse files
authored
Merge pull request #85 from WPO-Foundation/updates
Updates - ongoing
2 parents 34d94dc + c5562e7 commit f425694

9 files changed

Lines changed: 62 additions & 34 deletions

File tree

src/_includes/layouts/index.njk

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -9,7 +9,7 @@
99
<p>Each test can be run from different locations around the world, on real browsers, over any number of customizable network conditions.</p>
1010
<p><a href="/getting-started" class="btn">Get started →</a></p>
1111
</div>
12-
<img class="hero" src="/img/wpt-teaser.png" alt="">
12+
<img class="hero" src="/img/results-summary.png" alt="">
1313

1414
</div>
1515
<main class="wide">
@@ -32,4 +32,4 @@
3232

3333
{% include 'footer.html' %}
3434
</body>
35-
</html>
35+
</html>

src/getting-started.md

Lines changed: 60 additions & 32 deletions
Original file line numberDiff line numberDiff line change
@@ -27,44 +27,72 @@ Finally, you need to decide what browser to use for the test. Different locatio
2727
After everything is configured the way you like, click on the "Start Test" button and your request will be sent to the test location for testing. The test may take a while to run depending on how many tests are ahead of yours (figure at least one minute for each test ahead of yours but it's not unusual for it to be even longer than that). Once the test is complete you will be presented with the results.
2828

2929
## Interpreting the Results
30-
The results screen can be a bit intimidating the first time you see it because there is a lot of information to consume but there are some key pieces of information to look at first.
3130

32-
### Optimization Grades:
33-
At the top of the results page are a set of grades for the most critical performance optimizations. These cover the basic optimizations that apply to just about all sites and anything that isn't an A or a B justifies some serious scrutiny and investigation.
31+
The results of a standard WebPageTest run begin on the summary page. This page starts with a written summary of how the site performed based on three categories: "Is it quick?", "Is it usable?", and "is it resilient?", which you can click to reach the Opportunities & Experiments page. Beneath the summaries, you'll find the metrics recorded by WebPageTest which include brief summaries beneath them to explain their purpose. These metrics will show for the median run and repeat run if repeat runs were selected up-front, and a preview of the visual page loading filmstrip shows below the metrics. After the WebPageTest metrics, you'll sometimes find additional metrics gethered by Google's CrUX report, which are collected anonomously for many sites from users in Chrome. And beyond that, you'll find some previews of each run's waterfall, with link to detail pages.
3432

35-
![](/img/qs_grades.png)
33+
!["results summary page"](/img/results-summary.png)
3634

37-
#### Keep-alive Enabled:
35+
## High-level Metrics
36+
![](/img/results-metrics.jpg)
37+
38+
### Time to First Byte
39+
The First Byte time is the time from when the user started navigating to the page until the first bit of the server response arrived. The bulk of this time is usually referred to the "back-end time" and is the amount of time the server spent building the page for the user.
40+
### Start Render:
41+
The Start Render time is the first point in time that something was displayed to the screen. Before this point in time the user was staring at a blank page. This does not necessarily mean the user saw the page content, it could just be something as simple as a background color but it is the first indication of something happening for the user.
42+
### First Contentful Paint
43+
How soon did text and images start to appear?
44+
### Speed Index
45+
The Speed Index is the average time at which visible parts of the page are displayed. It is expressed in milliseconds and dependent on size of the view port.
46+
### Largest Contentful Paint
47+
When did the largest piece of content in the viewport finish loading?
48+
### Cumulative Layout Shift
49+
How much did the layout within the viewport shift while the page was loading?
50+
### Total Blocking Time
51+
Total amount of time where the main thread was blocked by long tasts after the initial content was rendered
52+
### Page Weight
53+
This is the amount of data that the browser had to download in order to load the page. It is also commonly referred to as the "Page Size".
54+
### Carbon Footprint (_Experimental_)
55+
This is the estimated carbon equivalent of a webpage, calculated based upon green hosting statuses and page weight.
56+
57+
## Result Detail Pages
58+
59+
The results navigation offers links to deeper analysis of the test results.
60+
61+
![](/img/results-nav.png)
62+
63+
## Opportunities & Experiments
64+
65+
The opportunities and experiments page offers a breakdown of diagnostics that check for performance bottlenecks and when possible, offer no-code experiments that you can run to test whether various optimizations improve performance.
66+
67+
![](/img/results-oppsnexps.png)
68+
69+
Some Experiments are free to try but most of them are a premium feature that comes with WebPageTest Pro. After running an experiment, you'll see a comparison of the experiment run and a control run (which is the original site re-run through the experiments proxy server to create a comparable environment). This page can help determine if key metrics were improved.
70+
71+
You can [read more about Opportunities & Experiments on the WebPageTest blog](https://blog.webpagetest.org/posts/introducing-opportunities-and-experiments/).
72+
73+
## Carbon Control
74+
Carbon Control is a new Experimental feature that estimates a site's carbon footprint and allows you to run experiments to potentially improve that footprint. You can [read more about Carbon Control on the WebPageTest blog](https://blog.webpagetest.org/posts/carbon-control/).
75+
76+
![](/img/results-carboncontrol.jpg)
77+
78+
## Details Page
79+
The details result page provides additional metrics for each run and repeat run of a test as well as a waterfall for requests and connections that a site makes.
80+
81+
## Filmstrip View
82+
The filmstrip page provides a visual keyframe view of the page as it loaded. It also serves as a run comparison tool for multiple test run filmstrips. beneath the filmstrips, you can find waterfalls with a red overlay line that syncs its timing to the left edge of the filmstrips above. This allows you to explore what was happening in the browser at various visual moments in the filmstrip.
83+
84+
## Optimization Page:
85+
At the top of the optimization page are a set of grades for the most critical performance optimizations. These cover the basic optimizations that apply to just about all sites and anything that isn't an A or a B justifies some serious scrutiny and investigation.
86+
87+
### Keep-alive Enabled:
3888
Each request for a piece of content on the page (image, javascript, css, flash, etc) needs to be made over a connection to the web server. Setting up new connections can take a lot of time so it is best to re-use connections when you can and keep-alive is the way that is done. They are enabled by default on most configurations and are part of the HTTP 1.1 standard but there are times when they will be broken (sometimes unintentionally). Enabling keep-alives is usually just a configuration change on the server and does not require any changes to the page itself and can usually reduce the time to load a page by 40-50%.
39-
#### Compress Text:
89+
### Compress Text:
4090
Just about everything on a page that isn't an image or video is text of some kind (html, javascript, css). Text compresses really well and HTTP provides a way to transfer the files in compressed form. Enabling compression for text resources is usually just a server configuration change without requiring any changes to the page itself and can both improve the performance and reduce the costs of serving the content (by reducing the amount of data transmitted). Since text resources are usually downloaded at the beginning of the page (javascript and css), delivering them faster has a much larger impact on the user experience than excessive bytes on images or other content.
41-
#### Compress Images:
91+
### Compress Images:
4292
The image compression check just looks at photo images (JPEG files) and makes sure the quality isn't set too high. JPEG images can usually be compressed pretty substantially without any noticeable reduction in visual quality. We use a standard of compressing the images at a quality level of "50" in Photoshop's "Save for Web" mode but generally you should compress them as much as you can before they start to look bad. It's also not uncommon for other data to be included in photos, particularly if they came from a digital camera (information about the camera, lens, location, even thumbnail images) and some of that should be removed from images before being published to a web page (be careful to retain any copyright information).
43-
#### Cache Static Content:
93+
### Cache Static Content:
4494
Static Content are the pieces of content on your page that don't change frequently (images, javascript, css). You can configure them so that the user's browser will store them in a cache so if the user comes back to the page (or visits another page that uses the same file) they can just use the copy they already have instead of requesting the file from the web server. Successfully caching static content in the user's browser can significantly improve the performance of a repeat view visit (up to 80+% depending on the page) and reduces the load on the web servers. It can sometimes be tricky to implement caching without breaking a page though so don't just enable it blindly (you need to be able to change the file name for any files that you expect to change).
45-
#### Use of CDN:
95+
### Use of CDN:
4696
Each request for a piece of content to the web server has to travel from the user's browser all the way to the server and back. As you get further and further from the server this can become a significant amount of time (which adds up quickly as there are more requests on the page). Ultimately the time it takes is limited by the speed of light so there's not much you can do except to move your server closer to the users. That is exactly what a Content Distribution Network (CDN) does. They have servers all over the world that are close to users and they can serve a web site's static content from servers close to users. The only case where it doesn't make sense to use a CDN is if all of the users for a web site are close to the web server already (like for a community web site).
4797

48-
### High-level Metrics:
49-
The data table at the top of the results page gives you some high-level information about the page that was loaded:
50-
51-
![](/img/qs_metrics.png)
52-
53-
#### First View:
54-
The First View row is a test that was done with a browser that had its cache and cookies cleared out and represents what a first-time visitor to the page will experience.
55-
#### Repeat View:
56-
The Repeat View row is a test that was done immediately after the First View test without clearing out anything. The browser window is closed after the First View test and then a new browser is launched to do the Repeat View test. The Repeat View test represents what someone will see if they are coming back to the page some time after visiting it the first time (and is a best-case scenario since the test is re-visiting the page immediately).
57-
#### Document Complete:
58-
The metrics grouped together under the Document Complete heading are the metrics collected up until the browser considered the page loaded (onLoad event for those familiar with the javascript events). This usually happens after all of the images content have loaded but may not include content that is triggered by javascript execution.
59-
#### Fully Loaded:
60-
The metrics grouped together under the Fully Loaded heading are the metrics collected up until there was 2 seconds of no network activity after Document Complete. This will usually include any activity that is triggered by javascript after the main page loads.
61-
#### Load Time:
62-
The Load Time is the time from when the user started navigating to the page until the Document Complete event (usually when all of the page content has loaded).
63-
#### First Byte:
64-
The First Byte time is the time from when the user started navigating to the page until the first bit of the server response arrived. The bulk of this time is usually referred to the "back-end time" and is the amount of time the server spent building the page for the user.
65-
#### Start Render:
66-
The Start Render time is the first point in time that something was displayed to the screen. Before this point in time the user was staring at a blank page. This does not necessarily mean the user saw the page content, it could just be something as simple as a background color but it is the first indication of something happening for the user.
67-
#### Requests:
68-
This is the number of requests that had to be made by the browser for pieces of content on the page (images, javascript, css, etc).
69-
#### Bytes In:
70-
This is the amount of data that the browser had to download in order to load the page. It is also commonly referred to as the "Page Size".
98+

src/img/qs_browser.png

1.8 MB
Loading

src/img/qs_url.png

35.6 KB
Loading

src/img/results-carboncontrol.jpg

118 KB
Loading

src/img/results-metrics.jpg

48.1 KB
Loading

src/img/results-nav.png

41.8 KB
Loading

src/img/results-oppsnexps.png

177 KB
Loading

src/img/results-summary.png

190 KB
Loading

0 commit comments

Comments
 (0)