Wii U system can preload application into RAM Disk to enable faster launch times for applications. At this time, only executable files (RPX, RPL) can be preloaded. No data files can be preloaded.
As an example, when the user inserts a game disc, Wii U system can immediately start spinning up the disc and preload executable files into RAM Disk. This helps to reduce launch time when the user chooses to launch the game from Wii U system menu.
There are 2 methods for preloading:
preload.txt. This file contains the main object file (RPX) for the game and any statically-linked RPLs that the RPX depends on.
preload.txtfile that is associated with the application, and then starts to preload files. The Wii U application launch has several seconds of animation prior to starting launch activity. This time is a good opportunity to preload.
Maximum size that can be preloaded is currently 20 MB. A preload size calculation tool is available for size check.
When an optical disc is inserted, Wii U preloads the application and marks it as “sticky”. This will remain sticky until the disc is ejected or Wii U is powered down. If the application resides in flash memory (i.e. NAND), the same “sticky” policy applies. In addition, for application stored in flash memory, if the game (or title) is uninstalled, any cached items in RAM Disk for this application will be removed.
The RAM disk caching algorithm uses a “Least Frequently Used” (LFU) policy for memory management. This means that when the RAM disk is fully used, the eviction policy dictates that the least used item(s) will be removed from the RAM disk to allow room for the new items.
The preload file must be named
preload.txt and reside in the application's code directory. The file must be space and/or newline delimited, and ideally contain the following items:
The preload checker tool verifies that preload files meet all necessary requirements. It may also be used to generate a preload file by passing
-g as a command line argument.
To use the tool, use the following command from a Cafe Cygwin shell:
$ preloadcheck.sh [options] [optional path to the code folder]
$ preloadcheck.sh $ preloadcheck.sh helloworld_rpl/ $ preloadcheck.sh -g helloworld_rpl/
A demo is located in the directory
Building this demo will generate the files,
cos.xml, which are needed before running the preload checker tool. In this demo,
statically bound to
hello.rpx and should ideally be included in the preload file.
2013/12/04 Removed unused anchors.
2013/11/27 Worked anchors.
2013/05/08 Automated cleanup pass.
2012/08/21 Initial version.