High Performance Web Sites 132
Michael J. Ross writes "Every Internet user's impressions of a Web site is greatly affected by how quickly that site's pages are presented to the user, relative to their expectations — regardless of whether they have a broadband or narrowband connection. Web developers often assume that most page-loading performance problems originate on the back-end, and thus the developers have little control over performance on the front-end, i.e., directly in the visitor's browser. But Steve Souders, head of site performance at Yahoo, argues otherwise in his book, High Performance Web Sites: Essential Knowledge for Frontend Engineers." Read on for the rest of Michael's review.
The typical Web developer — particularly one well-versed in database programming — might believe that the bulk of a Web page's response time is consumed in delivering the HTML document from the Web server, and in performing other back-end tasks, such as querying a database for the values presented in the page. But the author quantitatively demonstrates that — at least for what are arguably the top 10 sites — less than 20 percent of the total response time is consumed by downloading the HTML document. Consequently, more than 80 percent of the response time is spent on front-end processing — specifically, downloading all of the components other than the HTML document itself. In turn, cutting that front-end load in half would improve the total response time by more than 40 percent. At first glance, this may seem insignificant, given how few seconds or even deciseconds it takes for the typical Web page to appear using broadband. But any delays, even a fraction of a second, accumulate in reducing the satisfaction of the user. Likewise, improved site performance not only benefits the site visitor, in terms of faster page loading, but also the site owner, with reduced bandwidth costs and happier site visitors.
| High Performance Web Sites | |
| author | Steve Souders |
| pages | 168 |
| publisher | O'Reilly Media |
| rating | 9/10 |
| reviewer | Michael J. Ross |
| ISBN | 0596529309 |
| summary | 14 rules for faster Web pages |
Creators and maintainers of Web sites of all sizes should thus take a strong interest in the advice provided by "Chief Performance Yahoo!," in the 14 rules for improving Web site performance that he has learned in the trenches. High Performance Web Sites was published on 11 September 2007, by O'Reilly Media, under the ISBNs 0596529309 and 978-0596529307. As with all of their other titles, the publisher provides a page for the book, where visitors can purchase or register a copy of the book, or read online versions of its table of contents, index, and a sample chapter, "Rule 4: Gzip Components" (Chapter 4), as a PDF file. In addition, visitors can read or contribute reviews of the book, as well as errata — of which there are none, as of this writing. O'Reilly's site also hosts a video titled "High Performance Web Sites: 14 Rules for Faster Pages," in which the author talks about his site performance best practices.
The bulk of the book's information is contained in 14 chapters, with each one corresponding to one of the performance rules. Preceding this material are two chapters on the importance of front-end performance, and an overview of HTTP. Together these form a well-chosen springboard for launching into the performance rules. In an additional and last chapter, "Deconstructing 10 Top Sites," the author analyzes the performance of 10 major Web sites, including his own, Yahoo, to provide real-world examples of how the implementation of his performance rules could make a dramatic difference in the response times of those sites. These test results and his analysis are preceded by a discussion of page weight, response times, YSlow grading, and details on how he performed the testing. Naturally, if and when a reader peruses those sites, checking their performance at the time, the owners of those sites may have fixed most if not all of the performance problems pointed out by Steve Souders. If they have not, then they have no excuse, if only because of the publication of this book.
Each chapter begins with a brief introduction to whatever particular performance problem is addressed by that chapter's rule. Subsequent sections provide more technical detail, including the extent of the problem found on the previously mentioned 10 top Web sites. The author then explains how the rule in question solves the problem, with test results to back up the claims. For some of the rules, alternative solutions are presented, as well as the pros and cons of implementing his suggestions. For instance, in his coverage of JavaScript minification, he examines the potential downsides to this practice, including increased code maintenance costs. Every chapter ends with a restatement of the rule.
The book is a quick read compared to most technical books, and not just due to its relatively small size (168 pages), but also the writing style. Admittedly, this may be partly the result of O'Reilly's in-house and perhaps outsource editors — oftentimes the unsung heroes of publishing enterprises. This book is also valuable in that it offers the candid perspective of a Web performance expert, who never loses sight of the importance of the end-user experience. (My favorite phrase in the book, on page 38, is: "...the HTML page is the progress indicator.")
The ease of implementing the rules varies greatly. Most developers would have no difficulty putting into practice the admonition to make CSS and JavaScript files external, but would likely find it far more challenging, for instance, to use a content delivery network, if their budget puts it out of reach. In fact, differences in difficulty levels will be most apparent to the reader when he or she finishes Chapter 1 (on making fewer HTTP requests, which is straightforward) and begins reading Chapter 2 (content delivery networks).
In the book's final chapter, Steve Souders critiques the top 10 sites used as examples throughout the book, evaluating them for performance and specifically how they could improve that through the implementation of his 14 rules. In critiquing the Web site of his employer, he apparently pulls no punches — though few are needed, because the site ranks high in performance versus the others, as does Google. Such objectivity is appreciated.
For Web developers who would like to test the performance of the Web sites for which they are responsible, the author mentions in his final chapter the five primary tools that he used for evaluating the top 10 Web sites for the book, and, presumably, used for the work that he and his team do at Yahoo. These include YSlow, a tool that he created himself. Also, in Chapter 5, he briefly mentions another of his tools, sleep.cgi, a freely available Perl script that tests how delayed components affect Web pages.
As with any book, this one is not perfect — nor is any work. In Chapter 1, the author could make more clear the distinction between function and file modularization, as otherwise his discussion could confuse inexperienced programmers. In Chapter 10, the author explores the gains to be made from minifying JavaScript code, but fails to do the same for HTML files, or even explain the absence of this coverage — though he does briefly discuss minifying CSS. Lastly, the redundant restatement of the rules at the end of every chapter, can be eliminated — if only in keeping with the spirit of improving performance and efficiency by reducing reader workload.
Yet these weaknesses are inconsequential and easily fixable. The author's core ideas are clearly explained; the performance improvements are demonstrated; the book's production is excellent. High Performance Web Sites is highly recommended to all Web developers seriously interested in improving their site visitors' experiences.
Michael J. Ross is a Web developer, freelance writer, and the editor of PristinePlanet.com's free newsletter.
You can purchase High Performance Web Sites from amazon.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.
Re:Rule #34: Don't be the first Java site of the d (Score:1, Insightful)
Re:Is it just me... (Score:3, Insightful)
What's suspicious about the fact that a book written by the creator of YSlow addresses the very issues that YSlow, a free open source Firefox extension, addresses? It would be pretty strange if it didn't.
If you want to be so paranoid about the intentions of an author, at least find one it's reasonable to be suspicious about in the first place.
The book would be a lot more believable... (Score:5, Insightful)
Doh! Test yer pages! (Score:4, Insightful)
Then every added feature has to be justified -- perceived added value versus cost-to-load. Sure, the artsies won't like you. But it isn't your decision or theirs. Management must decide.
For greater sophistication, you can measure your dl rates by file to see how much is in users caches. And decide whether these are also not a cause of slowness!
Interesting Points... (Score:2, Insightful)
Re:All my sites load fast (Score:4, Insightful)
Umm... there are plenty of content management systems (say, Cascade [hannonhill.com]) that manage content and publish it out to HTML. Even Dreamweaver's templating system will do this. Just because you use pure HTML, doesn't mean you have to lose out on sitewide management control.
Odd Summary (Score:4, Insightful)
Let's correct this summary a little bit. First, it's NOVICE Web developers who would think this. Any web developer worth their weight knows the basic idea that java, flash, and other things like it make a PC work hard. The website sends code, but the PC has to execute the code, rather than the website pushing static or dynamic HTML and having it simply render. We bitch and moan enough here on slashdot about flash/java heavy pages, I feel this summary is misdirected as if web developers here didn't know this.
Secondly, there's no argument, so Steve doesn't have to argue with anyone. It's a commonly accepted principle. If someone didn't learn it yet, they simply haven't learned it yet.
Now, I welcome a book like this because #1 it's a great tool for novices to understand the principle of optimization on both the server and the PC, and #2 because it hopefully has tips that even the above average admin will learn from. But I scratch my head when the summary makes it sound like it's a new concept.
Pardon me for nitpicking.
Re:gzip (Score:4, Insightful)
Advertising slows everything down (Score:3, Insightful)
Putting an adblocker of some sort or Mozilla Adblock Plus is a great way to speed up any page (from the user's point of view, of course).
Web 2.0 performance costs (Score:5, Insightful)
- Spike
Freeware OpenGL arcade game SOL, competitor in the 2008 Independent Games Festival: http://www.mounthamill.com/sol.html [mounthamill.com]
Sort of... (Score:3, Insightful)
And, in fact, a lot of web site developers fit one, two or three of the above categories. It's not just novices. a ridiculous percentage of websites suck performance-wise, and it's not just the myspaces and hacked up CMSes and such; a lot of corporate sites fall into this category as well, from financial institutions to ebay to auto manufacturers and dealers to swimming pool installation companies.
Still the same with web masters. (Score:3, Insightful)
Those Web designers should be called "Unemployed"
This is unnecessary - and dangerous (Score:3, Insightful)
Using AJAX you have to also remember that you're giving away all your code - and that any user with GreaseMonkey can REWRITE your code to do whatever they want. So your scenario only works out if 100% of your application data for all time is supposed to be viewable (at least) by all users. (Which is not to mention a significant number of other AJAX security potholes.)
Use AJAX to save page refreshes (eg Google Maps) - and only that. For any real world app, your server needs to control your data.
And if you need help implementing this, drop me a reply
Re:Interesting Points... (Score:3, Insightful)
Have read, mixed feelings (Score:4, Insightful)
I have looked at the book again now, and there seem to have been some changes. For example, there were only 13 rules when I was reviewing those before. Now there are 14. As one example, ETags were advised to not be used at all (IIRC, my biggest WTF about the book - if used correctly, ETags are marvellous things and compliment 'expires' very nicely), instead of the current 'only use if done correctly'. Some other things are nigh impossible to do correctly crossbrowser (think ETag + GZIP combo in IE6, AJAX caching in IE7, etc). To be honest, I found pretty much all of this stuff being WebDevelopment 101. If you're not at the level that you should be able to figure most of these things out for yourself, you probably won't be able to put them into practise anyway, and you should not be in a place where you are responsible for these things.
I might pick up this book just to read it again, see about the changes and read the full chapters, just to hear the 'other side of the story', but IMHO this book isn't worth it. In all honesty, the only thing I got out of it so far that I didn't know is the performance toll CSS expressions take (all expressions are literally re-evaluated at every mouse move), but I hardly used those anyways (only to fix IE6 bugs), and in response have written a jQuery plugin that does the required work at only the wanted times (and I've told you this now, so no need to buy the book).
My conclusion, based solely on the fairly large number if excerpts I've read is: if you're a beginner, keep this book off for a while. If you're past the beginner stage but your pages are strangly sluggish, this book is for you. If you've been around, you already know all this stuff.
Accessibility and search indexing (Score:3, Insightful)
Third-party content. (Score:3, Insightful)
Basically anything that's not under your control can slow your site down significantly.
Re:Solution (Score:3, Insightful)
sounds good, except you may or may not know that a lot of javascript implementations are sloooow. not to mention you usually have to set the no cache headers for everything in the page so your javascript works right.
I find that sites built with the method you describe are the asshole sites that fuck with browser history, disable the back button, try to disable the context menu, and those dumb ass tricks to get around the fact they don't know how to write proper server side code.
Could be reworded as follows:
AJAX isn't quite mature and it is still slow on those Wallmart PCs so I suggest that, in lieu of the AJAX client, I suggest that you simply apply a stylesheet to the XML with XSLT to provide the best of both worlds. But mature AJAX toolkits (such as GWT) are improving and do a speedy rendering job while adequately managing the browser history and other nuances of the UI.
There's no reason you can't make a fast serverside site (with ajax too, that works without the stupid tricks I described above), if you can't I suggest you educate yourself, or don't use a wallmart PC for production use.
I do most of my work in server-side work. I will disregard the evidence that was provided about the test environment from "years ago" and instead insult you as if you were my nemesis, instead of someone that I have never met prior to this discussion.
Fixed that for you.
Re:Actually my sites are commercial (Score:2, Insightful)
Also, don't the adds call some sort of script? I wouldn't call that static.