Make my desktop app appears to load/quit faster

I currently have a GUI single-threaded application in C++ and Qt. It takes a good 开发者_开发问答1 minute to load (read from disk) and ~5 seconds to close (saving settings, finalize connections, ...).

What can I do to make my application appear to be faster?

My first thought was to have a server component of the app that does all the works while the GUI component is only for displaying. The communication is done via socket, pipe or memory map. That seems like an overkill (in term of development effort) since my application is only used by a handful of people.

The first step is to start profiling. Use an actual, low-overhead profiling tool (eg, on Linux, you could use oprofile), not guesswork. What is your app doing in that one minute it takes to start up? Can any of that work be deferred until later, or perhaps skipped entirely?

For example, if you're loading, say, a list of document templates, you could defer that until the user tells you to create a new document. If you're scanning the system for a list of fonts, load a cached list from last startup and use that until you finish updating the font list in a separate thread. These are just examples - use a profiler to figure out where the time's actually going, and then attack the code starting with the largest time figures.

In any case, some of the more effective approaches to keep in mind:

• Skip work until needed. If you're doing initialization for some feature that's used infrequently, skip it until that feature is actually used.
• Defer work until after startup. You can take care of a lot of things on a separate thread while the UI is responsive. If you are collecting information that changes infrequently but is needed immediately, consider caching the value from a previous run, then updating it in the background.

For your shutdown time, hide your GUI instantly, and then spend those five seconds shutting down in the background. As long as the user doesn't notice the work, it might as well be instantaneous.

You could employ the standard trick of showing something interesting while you load.

Like many games nowadays show a tip or two while they are loading

It looks to me like you're only guessing at where all this time is being burned. "Read from disk" would not be high on my list of candidates. Learn more about what's really going on.

Use a decent profiler.

Profiling is a given, of course.

Most likely, you may find I/O is substantial - reading in your startup files. As bdonlan notes, deferring work is a standard technique. Google 'lazy evaluation'.

You can also consider caching data that does not change. Save a cache in a faster format, such as binary. This is most useful if you happen to have a large static data set read into something like an array.