In theory there’s no difference between theory and practice. In practice, there is. That’s why we prefer to try new ideas out in the real world and see which features actually helped users get where they want to go. In Chrome we call these tests Field Trials, and they’ve been part of every install steadily making Chrome better since day one. For example, Field Trials helped us improve our Omnibox pre-rendering by about 70 percent - making about 1 in 3 Omnibox navigations faster by a second or more.

If you’re contributing to Chrome, you should consider using Field Trials to help tune your features. Recently we’ve added infrastructure to help make designing and deploying these tests easier than ever. Field Trials will now have a regular update cycle similar to the one that delivers the newest version of Chrome to users, making it easier to rapidly release and retire new variations. We’ve also centralized the logic of which variations are active so that its easy for developers on M21 or higher to reset their variation state, using the --reset-variation-state command line flag. To learn more about variations of Chrome, check out Field Trials at the Chromium project.

 Posted by Tyler Odean, Product Manager

Last year, Google’s Adam Langley, Nagendra Modadugu, and Bodo Moeller proposed SSL False Start, a client-side only change to reduce one round-trip from the SSL handshake.

We implemented SSL False Start in Chrome 9, and the results are stunning, yielding a significant decrease in overall SSL connection setup times. SSL False Start reduces the latency of a SSL handshake by 30%¹. That is a big number. And reducing the cost of a SSL handshake is critical as more and more content providers move to SSL.

Our biggest concern with implementing SSL False Start was backward compatibility. Although nothing in the SSL specification (also known as TLS) explicitly prohibits FalseStart, there was no easy way to know whether it would work with all sites. Speed is great, but if it breaks user experience for even a small fraction of users, the optimization is non-deployable.

To answer this question, we compiled a list of all known https websites from the Google index, and tested SSL FalseStart with all of them. The result of that test was encouraging: 94.6% succeeded, 5% timed out, and 0.4% failed. The sites that timed out were verified to be sites that are no longer running, so we could ignore them.

To investigate the failing sites, we implemented a more robust check to understand how the failures occurred. We disregarded those sites that failed due to certificate failures or problems unrelated to FalseStart. Finally, we discovered that the sites which didn’t support FalseStart were using only a handful of SSL vendors. We reported the problem to the vendors, and most have fixed it already, while the others have fixes in progress. The result is that today, we have a manageable, small list of domains where SSL FalseStart doesn’t work, and we’ve added them to a list within Chrome where we simply won’t use FalseStart. This list is public and posted in the chromium source code. We are actively working to shrink the list and ultimately remove it.

All of this represents a tremendous amount of work with a material gain for Chrome SSL users. We hope that the data will be confirmed by other browser vendors and adopted more widely.

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¹Measured as the time between the initial TCP SYN packet and the end of the TLS handshake.

Posted by Mike Belshe, Software Engineer

Foreword: When we released Google Chrome almost two years ago, we also released the source code under an open-source license. Just as Firefox, WebKit, and other open source projects helped to drive the web forward, we wanted to follow suit and ensure that others could use the code we developed to make their products better. The Chromium codebase provides a complete browser to build on, so that if you want to focus on one particular piece, such as drastically changing the user interface, you can do that without having to worry about how to get amazing performance in the rest of the browser.

Recently, Flock released a new beta version of their browser built on top of the Chromium codebase. For those of us in the Chromium project, this is extremely exciting and encouraging. We believe that users having a choice between multiple browsers is a great thing, as it spurs innovation and competition, and lets users choose a browser that provides the best experience for them. Flock brings an innovative approach to their "social web browser," and we are glad to welcome them into the Chromium community. As part of that, we wanted to offer the team behind Flock an opportunity to talk about the ideas behind Flock, how Chromium helped them in achieving their goals, and their vision for the future. What follows is a perspective from Clayton Stark, VP Engineering at Flock.

When Flock began developing its first web browser five years ago, "the social web" was a small, niche market. Today social is the mainstream web, and this evolution in the market drove our development roadmap. With the new Flock browser, our engineering team focused on designing a straightforward and integrated social dashboard that delivers an experience simple enough for a mass audience. This is where the technology behind Chromium came into the picture for Flock. As Chromium emerged, we saw that not only was there significant improvements to performance, but also apparent was a simple and elegant user interface and architecture across all the various systems.

A core goal of new Flock is to keep our users in touch with all of their friends and feeds with a minimum of configuration, and at the same time, make it fun and simple. With all of the users’ feeds and social activity streams flowing into the scrolling sidebar, we knew the performance had to be first-rate, and that techniques we used for earlier versions of Flock were unlikely to perform at scale. With Chromium under the hood, we were able to leverage web workers, and that, combined with the raw horsepower of V8, allowed us to scale the use of the sidebar to manage very large data sets (in the first few weeks after the beta launched we saw a few hundred million activities flowing into Flock’s sidebar). Most importantly, benchmark testing shows us that New Flock with Chromium performs in the top-tier of all browsers available in the market.

Clearly the web is evolving very quickly, and we are seeing more and more people discovering content through their friends. The Flock team is energized by the big developments coming fast in this emerging, interest-graph-enabled web, and we have a roadmap in front of us that we are really excited about. The browsing platform needs to continue to mature at a rapid pace to support the dramatic changes in online user behavior. And, as it does, we already see the performance and power in Chromium that we need to allow us to focus on the innovations we want to bring forward, on top of the platform.

So, I’d like to send out a huge thanks on behalf of the Flock team to all those who have contributed to the Chromium project. Your work has made our project possible, and made new Flock our best release ever.

Clayton Stark, VP Engineering

Flock, Inc.

Posted by Ian Fette, Product Manager