[Qt-interest] Qt Application Compiles very Slow on Windows Machines

[Konrad Rosenbaum]

Hi,

[sorry, some ranting ahead]

On Friday 09 April 2010, Aaron Lewis wrote:
> 	Mingw Compiles very slow on Windows , while my Gentoo goes extremely
> fast.

This is a problem of Windows. Windows is simply not well prepared to create 
new processes or handle something as complex as accessing files in a timely 
manner.

I usually develop my apps on a Linux box (even one in a Virtualbox running 
on Windows will do better than plain Windows) and only do the release 
compile and testing on Windows. This way I spare myself the frequent and 
agonizing wait times during development - my projects are big enough to 
fetch a cup of coffee during a recompile on Linux and enough for extended 
lunch during recompile on Windows.

Typical Windows programs work around those OS problems by using thread pools 
instead of processes and doing LOTS of caching themselves - eg. MS visual 
studio compiles a whole sub-project in one compiler process, which doesn't 
start to write until it is done compiling and linking and typical Windows 
DVD players do all the pre-fetching themselves. On the other hand all GNU 
tools (incl. make and gcc) rely on the OS having cheap processes and good 
caching.

Just for fun: check out the descriptions of fflush and fsync on MSDN and in 
the POSIX standard. That some m*r*n at MS didn't understand the difference 
sent me on a two weeks search for the cause of a factor 60 performance 
difference in an embedded database between Linux and Windows.



	Konrad
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