[CMake] Obtaining improved GNU make performance on Makefiles generated by cmake

[Bill Hoffman]

Filipe Sousa wrote:
> Alan W. Irwin wrote:
>> On 2008-03-25 14:28-0400 Bill Hoffman wrote:
>>
>>> --- build all of paraview with nothing needing a build:
>>>
>>> 2.6
>>> make  15.21s user 5.55s system 74% cpu 28.049 total
>>> make  15.44s user 5.35s system 98% cpu 21.073 total
> 
> make -j5
> 
> real    6m13.039s
> user    20m42.308s
> sys     2m43.996s
> 
>> user+system = 20.76s and 20.79s for the two runs.
>>>
>>> 2.4
>>> make  14.40s user 5.09s system 59% cpu 32.793 total
>>> make  14.73s user 4.74s system 98% cpu 19.684 total
>> user+system = 19.49s and 19.47s for the two runs
> 
> make -j5
> 
> real    6m14.700s
> user    20m39.125s
> sys     2m46.430s
> 

Is that 6 minutes??  The test is to run make in a tree that has 
everything already built.  We not trying to measure the speed of the 
compiler but rather the speed of make checking the depend information.

-Bill