Neil's Place

February 17, 2003

10:41 PM XUL and the performance thing

There are a number of people on various Mozilla forums that seem to be under the impression that any performance problems in Mozilla are caused by XUL. I'm not sure why they have this impression. I suspect that they see the various text files used and assume that they must take a long time to load and parse. I suspect, as with many people that complain about performance or resource issues, that they don't actually understand how other systems work. Here is a description of what happens when a window is opened in Mozilla:

XUL, scripts and other files are read from the JAR archive files in Mozilla's chrome directory. They are interpreted and compiled and a post-processed version is stored into a binary file (the fastload file) and saved to disk. This step is only done the first time you ever open the window -- the binary file is used from then on.

Since that step is not repeated again, the following is what happens every time afterwards:

What happens when a window is opened in Mozilla

When a window needs to be opened, the widget definitions and the layout of the window is loaded from the binary fastload file. The UI toolkit constructs objects for each item from the fastload file. Those objects, along with the toolkit, determine how to place themselves on the window. The UI toolkit calls drawing commands (line drawing, image drawing, etc...) to draw the elements to the screen.

Now let's look at what happens in other GUI systems, such as Windows 3.0 and every version after it, on all versions of the Macintosh, in Visual Basic, and Delphi, and in many other UI toolkits.

Click this button and note the differences in the paragraph above.

Note the similarities?

It should also be noted that Mac OS X applications also store their UI's in various external files, some of which are plain text files (or XML files), which get interpreted when needed. And how many people have you seen complaining about how slow Safari or Chimera are?

There are no "extra layers" as some are fond of mentioning. XUL widgets are read from a file as other systems do and are placed and drawn using low-level drawing functions. Where are these extra layers these XUL detractors often mention? I don't see them.

The truth is, there is no architectural flaw in the design of XUL that would make it slow, as it doesn't really operate any differently from other GUI toolkits or native UI systems. Thus, if it is the XUL component that causes any performance issues, they should be fixable over time, since the issue isn't a by-design issue, but an implementation specific one.

What I mean is that one could construct a different implementation of XUL that used all of the same file formats, but faster, since XUL's design is not fundamentally different from other UI toolkits in terms of how it loads content.

Here is a test to see if Mozilla takes too long to start:

  • Count the number of seconds Mozilla takes to start up. Multiply by the number of times you might start it in a month.
  • Count the number of seconds (or minutes) it took you to write lengthy rants about Mozilla's performance over a month long period on the newsgroups.

If the second value is greater, you obviously have lots of time. If the first value is greater than you have realized that 5 seconds of your life each day isn't worth getting stressed out about.

Comments ( 2 )

February 16, 2003

12:52 PM From n.p.d.xul

A XUL-based Amazon browser. Interesting.

Comments ( 29 )

February 14, 2003

10:33 PM I can see it now...

Terrorist 1: It seems the Americans won.

Terrorist 2: Did they? That duct tape may have defeated us. But the Americans won't stop there. They'll buy more and more duct tape, and soon, they will buy so much duct tape, it will destroy them all!

Evil laughs ensue.

Comments ( 9 )

February 12, 2003

8:03 PM A Sad Day

Let's say you've been working on project for three months and the launch day is this week. Which do you do?

  1. Do last minute testing to ensure it works properly.
  2. Sack most of your employees.

Can you guess which choice was actually selected? At times like this, you wonder whether you'd be better off working for AOL instead.

Comments ( 35 )

February 10, 2003

7:27 PM It really is Mozilla 101

It seems that learning 101 things Mozilla can do that IE cannot is reading material for a web development course. The site also has some useful Mozilla configuration tips. Make sure to try the links on the left too.

Speaking of that, what is all about?

Comments ( 32 )

5:10 PM XUL Examples

If you are looking for some XUL examples, look here, which has a pile of panels containing various arrangements of the XUL widgets.

Comments ( 5 )

February 9, 2003

11:46 AM What the feedback button in Safari really does

After weeks of intense study, reverse engineering and information from spies located deep within Apple, I have discovered what really happens when you click the feedback button in Safari, as indicated in the following code:

void FeedbackButtonClicked(void)
  String *subjects={
    "I really need to have tabbed browsing.",
    "I don't like the brushed metal appearance.",
    "I would like an integrated Mail client.",
    "I was reading, like a Web page of one of my friends
     and, like, then it crashed or something! It was, like,
     gone! I was totally... bummed out.",
    "Where may I go to sacrifice myself so that Steve Jobs
     may be appeased?"
  String subject=SelectRandomSubject(subjects);

Comments ( 16 )

February 8, 2003

6:34 PM The latest poll results are in!

According to the latest poll, people are most interested in seeing more XUL examples. Perhaps I will try to post some more examples of things that might be more complex, such as trees, overlays, DOM stuff and so on.

On the disturbing side though, an equal number of people would like to see pictures of Blake Ross naked. You do realize that he is only 8 years old? It might even be illegal just to think about it.

That said, there is a site dedicated to providing top quality pictures of Blake Ross naked, without having to worry about the legal issues.

Comments ( 24 )