[CMake] slow CMake performance configuring builds on remote SMB servers

[Bill Hoffman]

Philip Lowman wrote:
> Hi,
>
> We have somewhat of a large CMake project consisting of about 25 
> libraries.  Configuring on Linux over NFS is a snap taking only a few 
> seconds.  Configuring on a local C:\ for the Windows build is also 
> very fast only taking a few seconds.
>
> When we go to configure a build on a remote file server (using either 
> Samba or Windows XP File Sharing) we notice a dramatic slowdown in 
> performance.  Suddenly, initial configuration and generation of VCproj 
> files takes about 2-3 minutes as opposed to about 20 seconds with the 
> hard drive.  If I nuke CMakeCache.txt and reconfigure from scratch it 
> takes about the same amount of time which seems to indicate that there 
> is _no_ SMB file caching going on.
>
> Part of me thinks this is just a flaw with Windows XP but I'm having a 
> hard time believing that it's really this bad.
>
> I was wondering if anyone could report on their experiences 
> configuring a build with source and binary directories located on a 
> remote file server with Windows XP?
>
Is it mostly sending time in try-compile stuff?  If so, it might be 
possible that we could add some sort of cmake temp directory that was 
not under the build tree to run try-compile tests in.  Then that could 
be set to a local disk.   Once you have run CMake the first time, is it 
fast after that?

-Bill