[CMake] FYI - From Ninja-build mailing list - Fwd: Proposal: restat rules

[Bill Hoffman]

On 10/5/2011 4:13 PM, Peter Kümmel wrote:
> On 05.10.2011 20:38, Alexander Neundorf wrote:
>> On Wednesday 05 October 2011, Peter Kümmel wrote:
>>> And here some numbers to compare it with Qt's qmake.
>>> I've used this project: http://kst-plot.kde.org/
>>> which supports qmake and cmake.
>>>
>>> Running make/ninja on a fresh compiled project
>>> with warm caches (in seconds):
>>>
>>> qmake cmake Ninja
>>> Makefiles makefiles
>>>
>>> -j1 0.5-0.8 1.6-1.9 0.11-0.14
>>> -j2 0.6-0.8 1.3-1.4 0.11-0.13
>>> -j4 0.6-0.7 1.1-1.4 0.10-0.13
>>>
>>>
>>> Summary:
>>> - Ninja is the fastest
>>> - cmake Makefiles are really slow
>>> - parallel jobs doesn't help much in this special case
>>

OK, so I think this project is way too small for this test.  There is 
some fixed overhead in the process here, and we are seeing it.  We are 
talking about .5 seconds difference to check a whole build system.  If 
you want to do tests like this, you need a much bigger project.  I am 
sure that CMake will not be 50% slower for a larger project where we are 
not comparing .5 seconds to 1.1 seconds or .1 seconds.

-Bill