[CMake] makefile to CMakeLists.txt, possible?

[Michael Wild]

On 2. Sep, 2010, at 10:04 , Mike McQuaid wrote:

> 
> On 2 Sep 2010, at 08:49, Chiheng Xu wrote:
> 
>> Suppose you have a ultra large project,  it will consume 5 minutes to
>> CMake,  2 hours to build serially.  If you have an 64 Cores ccNUMA
>> systems, like Xeon 7500 (8 Cores * 8),  theretically, you will have a
>> 60+ accelaration in parallel build.  Theretically,  it will consume
>> less than 2 minutes to parallelly build, but it will also consume 5
>> minutes to serially CMake.  So, If you "cache" the Makefiles, it will
>> only consume less than 2 minutes to build.
> 
> First of all, I'm not aware of any development teams using that level of hardware and I doubt yours are either. Secondly, you'll find that as the CPU power grows, building is limited by disk IO and memory bandwidth rather than CPU power.
> 
> Regardless, what you are saying is that it will take 2 minutes to build EACH TIME and 5 minutes to run CMake ONCE (as you said developers rarely ever touch CMake files).
> 
> If you want to use Makefiles, fine, but without benchmarks your argument is pretty meaningless FUD against CMake and other makefile generators.

Oh, and yes: Ever timed "gcc -M" which is the usual approach to dependency-generation of hand-crafted Makefiles? THAT is slow. ;-)

Michael