Chrome Memory Usage - Good and Bad

Measuring memory


If you're measuring memory in a multi-process application like Google Chrome, don't forget to take into account shared memory. If you add the size of each process via the Windows XP task manager, you'll be double counting the shared memory for each process. If there are a large number of processes, double-counting can account for 30-40% extra memory size.


To make it easy to summarize multi-process memory usage, Google Chrome provides the "about:memory" page which includes a detailed breakdown of Google Chrome's memory usage and also provides basic comparisons to other browsers that are running.


Multi-process Model Disadvantages


While the multi-process model provides clear robustness and performance benefits, it can also be a setback in terms of using the absolute smallest amount of memory. Since each tab is its own "sandboxed" process, tabs cannot share information easily. Any data structures needed for general rendering of web pages must be replicated to each tab. We've done our best to minimize this, but we have a lot more work to do.


Example: Try opening the browser with 10 different sites in 10 tabs. You will probably notice that Google Chrome uses significantly more memory than single-process browsers do for this case.


Keep in mind that we believe this is a good trade-off. For example; each tab has it's own JavaScript engine. An attack compromising one tab's Javascript engine is much less likely to be able to gain access to another tab (which may contain banking information) due to process separation. Operating systems vendors learned long ago that there are many benefits to not having all applications load into a single process space, despite the fact that multiple processes do incur overhead.


Multi-process advantages


Despite the setback, the multi-process model has advantages too. The primary advantage is the ability to partition memory for particular pages. So, when you close a page (tab), that partition of memory can be completely cleaned up. This is much more difficult to do in a single-process browser.


To demonstrate, lets expand on the example above. Now that you have 10 open tabs in a single process browser and Google Chrome, try closing 9 of them, and check the memory usage. Hopefully, this will demonstrate that Google Chrome is actually able to reclaim more memory than the single process browser generally can. We hope this is indicative of general user behavior, where many sites are visited on a daily basis; but when the user leaves a site, we want to cleanup everything.

Google Chrome Speed

The JavaScript virtual machine was considered a sufficiently important project to be split off (as was Adobe/Mozilla's Tamarin) and handled by a separate team in Denmark. Existing implementations were designed "for small programs, where the performance and interactivity of the system weren't that important," but web applications such as Gmail "are using the web browser to the fullest when it comes to DOM manipulations and Javascript." The resulting V8 JavaScript engine has features such as hidden class transitions, dynamic code generation, and precise garbage collection. Tests by Google show that V8 is about twice as fast as Firefox 3 and the Safari 4 beta.

Several websites have performed benchmark tests using the SunSpider JavaScript Benchmark tool as well as Google's own set of computationally intense benchmarks, which includes ray tracing and constraint solving. They unanimously report that Chrome performs much faster than all competitors against which it has been tested, including Safari, Firefox 3, Internet Explorer 7, and Internet Explorer 8. While Opera has not been compared to Chrome yet, in previous tests, it has been shown to be slightly slower than Firefox 3, which in turn, is slower than Chrome.Another blog post by Mozilla developer Brendan Eich compared Chrome's V8 engine to his own TraceMonkey Javascript engine which is newly introduced in Firefox 3.1alpha, stating that some tests are faster in one engine and some are faster in the other, with Firefox 3.1a faster overall. John Resig, Mozilla's JavaScript evangelist, further commented on the performance of different browsers on Google's own suite, finding Chrome "decimating" other browsers, but he questions whether Google's suite is representative of real programs. He states that Firefox performs poorly on recursion intensive benchmarks, such as those of Google, because the Mozilla team has not implemented recursion-tracing yet.

Chrome also uses DNS prefetching to speed up website lookups

Google chrome built for Building a secure browser is a top priority for the Chromium team; it's why we spend a lot of time and effort keeping our code secure. But as you can imagine, code perfection is something almost impossible to achieve for a project of this size and complexity. To make things worse, a browser spends most of its time handling and executing untrusted and potentially malicious input data. In the event that something goes wrong, the team has developed a sandbox to help thwart any exploit in two of the most popular vectors of attack against browsers: HTML Rendering and JavaScript execution.

Google Chrome

Google Chrome is a browser that combines a minimal design with sophisticated technology to make the web faster, safer, and easier.




The story behind Google Chrome













Watch a video from the development team on the thinking and features behind Google Chrome.
Watch the video









Read about the technology









Look under the hood of Google Chrome in this comics interpretation of key engineering decisions, by Scott McCloud.
Read the book







Google Chrome is a free web browser developed by Google. The name is derived from the graphical user interface frame, or "chrome", of web browsers. Chromium is the name of the open source project behind Google Chrome, released under the BSD license. It is feature-complete compared to Chrome, but the user interface is less polished.
A beta version for Microsoft Windows was released on 2 September 2008 in 43 languages.

Announcement
The release announcement was originally scheduled for 3 September 2008, and a comic by Scott McCloud was to be sent to journalists and bloggers explaining the features of and motivations for the new browser. Copies intended for Europe were shipped early and German blogger Philipp Lenssen of Google Blogoscoped made a scanned copy of the 38-page comic available on his website after receiving it on 1 September 2008. Google subsequently made the comic available on Google Books and their site and mentioned it on its official blog along with an explanation for the early release.

Beta release
A beta version for Microsoft Windows (XP and later only) was released on 2 September 2008 in 43 languages. Mac OS X and Linux versions are under development.
On 2 September, a CNET news item drew attention to a passage in the terms of service for the initial beta release, which seemed to grant to Google a license to all content transferred via the Chrome browser.The passage in question was inherited from the general Google terms of service.The Register summarized the passage as "Your copyright goes up in smoke." On the same day, Google responded to this criticism by stating that the language used was borrowed from other products, and removed the passage in question from the Terms of Service.[17] Google noted that this change would "apply retroactively to all users who have downloaded Google Chrome." There were subsequent concerns about the browser's use of an unusual tracking feature that sends information about visited websites back to Google. The company stated that this is only enabled when users opt in by checking the option "help make Google Chrome better by automatically sending usage statistics and crash reports to Google" when installing the browser.
The first release of Google Chrome passed the Acid1 and Acid2 tests. While it has not yet passed the Acid3 test, Google Chrome scored 78/100—higher than both Internet Explorer 7 (14/100) and Firefox 3 (71/100), but lower than Opera's 84/100. When compared to equivalent "preview" or beta builds, Chrome scored lower than Firefox (85/100), Opera (91/100), and Safari (100/100), but still higher than Internet Explorer (21/100).

Chromium releases
On 15 September 2008, CodeWeavers released an unofficial bundle of a WINE derivative and Chromium Developer Build 21 for Linux and Mac OS X, which they dubbed "CrossOver Chromium". An unofficial workaround for use with Windows 2000 is also available.