[cmake-developers] CMake master slowdown in generation step

[Brad King]

On 04/08/2014 08:00 PM, Stephen Kelly wrote:
> adb96ae67e2ae5d8ab543fc60f11750a42ed0c41 (after latest optimization)
[snip]
> My new optimizations make the VTK time comparable with before-refactor on my 
> machine.

Great!  In my VTK test case posted previously the times are now:

 real    0m17.653s
 user    0m16.292s
 sys     0m1.016s

 real    0m17.476s
 user    0m16.216s
 sys     0m0.916s

The commit message in

 cmTarget: Short-circuit language computation if context independent.
 http://cmake.org/gitweb?p=cmake.git;a=commitdiff;h=b1c3ae33

is particularly effective in explaining the problem.  The change
that commit makes removes most of the cost of the new feature
(generator expressions in SOURCES) for projects not using it.

We'll see how the change does on tonight's dashboard.

Thanks,
-Brad