![]() ![]() ![]() (KDE) kdeinit is used to start applications.QApplication constructor already ran), the app startup is perceived considerably faster. Since all initialization is already done (e.g. Background: MeeGo is pre-launching a few processes in the background that wait for the actual app to launch.Note: You have to rewrite a small portion of your app, and you need to compile your app as position independent executable.Note: Although the boosters are part of MeeGo, the core parts are written in play C++ and can be re-used on other platforms as well.See Harmattan Booster for Qt Quick Applications on how to enable your Qt Quick applications to be boosted and the MeeGo launcher documentation on how to boost Qt and generic apps. (MeeGo) MeeGo supports "boosted" applications.(GNU ld) Use the LD_DEBUG environment variable to output statistics from the dynamic linker.valgrind: provides support via callgrind/cachegrind to measure the time spent before your main function, which includes symbol resolving and the time spent in initialization code for dependent libraries.GNU hash style improves startup time by improving the time to resolve symbols. This is the default on Linux, however, some toolchains might still default to the old sysv hash style, which has slower symbol lookup when using shared libraries. (GNU ld) Make sure to use GNU style hashes for symbol lookup ( -hash-style=gnu).See for example QtCore.dynlist in the QtCore source tree. Note: You can create a whitelist of symbols that will ignore the -Bsymbolic-functions switch, using the -dynamic-list parameter.There's a QMAKE variable QMAKE_LFLAGS_BSYMBOLIC_FUNC that expands to the corresponding linker flag if the linker supports symbolic functions.Note: Side-effects are that it's impossible to use LD_PRELOAD to override a symbol in a library.The effect is that every function call within your library will be initially faster since there's no lookup required. This tells the linker to use direct local jumps to symbols within your library instead of trying to resolve them by the usual means. (GNU ld) Use -Bsymbolic-functions for your shared libraries.To build Qt with LTO, configure it with -reduce-relocations -ltcg (LTCG stands for Link-Time Code Generation).Background: By creating usage statistics of your application, the linker can re-arrange the object code to improve loading time.Link Time Optimization (LTO) or Whole Program Optimization (WPO) can be used to improve startup times.Application level - this includes everything that the app itself can do to start up faster.Platform level - this includes various approaches that platforms offer.Toolchain level - this includes various optimization in the linker, the compiler and the dynamic linker.The approaches are separated in three areas: Feel free to discuss this page and share your knowledge by improving this page. This page lists various approaches on how to optimize application startup time. 1 How to optimize application startup time. ![]()
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