[CMake] Scanning dependencies of target xxx is very slow.

[Bill Hoffman]

On 6/5/2011 11:28 PM, jianhua wrote:
> Hi Neundorf;
>
> Thanks for your kindly response on this issue.
>
>>Usually  it  is  not  that  slow.
>>Can  you  give  us  some  more  information  ?
>>Of  how  many  files  consists  your  target  approximately  ?
>>Under  which  operating  system  ?
>>Is  it  maybe  on  NFS  or  samba  ?
>
>
> I try to build a lib based on about 300 source files.
> OS: Ubuntu 10.04 based on Oracle VM VirtualBox.
> CMKAE: V 2.8.3
>
> I use NFS,  files share between WinXP and VM VirtualBox, but I don't think it is root cause here, since if only using native Linux Ext3, the same, very slow to scan dependency.
>
> Now I use make mylib/fast to go on, otherwise it will block undergoing process.
>
> My question: which factors will cause it so low?
>
> a) Bad design, header files dependency so much.
> b) CMake  INCLUDE_DIRECTORIES, too many include?
> d) ...
>
> Thanks for your help.
>

You should look at ./CMakeFiles/YourLib.dir/depend.make.  What is in 
that file?  You can also do a make VERBOSE=1, and see exactly which part 
of the process is taking a long time.

-Bill