[distcc] homogeneous environments

[Robert W. Anderson]

I have an environment where we have many nodes potentially available for 
compilation, and all of them see the same file spaces via NFS.  We are 
seeing decent performance out of distcc 3.1 using pump mode, but from 
reading the docs there may be big performance gains left to wring out in 
this special(?) case.

If I understand correctly, distcc's pump mode finds a set of header 
files necessary to send along with the source file to enable compilation 
on a remote node.  In a homogeneous environment, it seems both steps 
here are unnecessary if the master and slave nodes are more or less 
indistinguishable in terms of compiler, sources, and headers.

I think we could really achieve some screaming compile times (over 
thousands of source files) if these steps could be bypassed with the 
user's explicit acknowledgement that he is making assumptions about the 
homogeneity of his build server machines.

How extensive would the modifications be to support such an 
optimization?  It was not clear to me after a few minutes of poking 
around in the source, and thought I'd seek an expert opinion first.

Thanks,
-- 
Robert W. Anderson
Center for Applied Scientific Computing
Email: anderson110 at llnl.gov
Tel: 925-424-2858  Fax: 925-423-8704