Nglayout.debug.disable xul fastload

From MozillaZine Knowledge Base

The title given to this article is incorrect due to technical limitations. The correct title is nglayout.debug.disable_xul_fastload.

This article describes the preference nglayout.debug.disable_xul_fastload. To add, delete, or modify this preference, you will need to edit your configuration — do not edit this article.

1 Background
2 Possible values and their effects
- 2.1 True
- 2.2 False
3 Caveats
4 Previous effects
5 First checked in
6 Has an effect in
7 Related bugs
8 Related preferences
9 External links

[edit]

Background

To improve performance, Mozilla saves a “compiled” version of the XUL and JavaScript to disk periodically so that it does not have to re-parse the data from chrome files on startup. This caching (often referred to as “XUL FastLoad” or just “FastLoad”) significantly decreases the time it takes to do a cold start of a Mozilla application.

The file to which the serialized data is saved differs by platform. On OS X it’s XUL FastLoad File; on Linux it’s xul.mfasl; and on Windows it’s XUL.mfl.

[edit]

Possible values and their effects

[edit]

True

Do not save serialized XUL/JS to disk.

[edit]

False

Save serialized versions of parsed XUL/JS to disk for faster startup times. (Default)

[edit]

Caveats

There is (unsurprisingly) a performance hit associated with setting this preference to true.
XUL FastLoad works without the XUL cache on, but FastLoad’s effects will be limited to JavaScript.
Conversely, the XUL cache works without FastLoad, but the cache will not be saved between Mozilla sessions.

[edit]

Previous effects

Until mid-2002, FastLoad (and thus this preference) was only concerned with the serialization of JavaScript. FastLoad began serializing XUL documents after bug 112064 was fixed.

[edit]