[Boost-build] Serializing linking

From: K. Noel Belcourt (kbelco_at_[hidden])
Date: 2007-12-05 23:53:43

Hi,

Strictly serializing all gcc linking is a tad draconian if you have a  
multi-processor system.  Does anyone know an easy way to generalize  
the semaphore so we could, for example, build -j16 but link with four  
processors?

     # Serialize execution of the 'link' action, since
     # running N links in parallel is just slower.
     # For now, serialize only gcc links, it might be a good
     # idea to serialize all links.
     JAM_SEMAPHORE on $(targets) = <s>gcc-link-semaphore ;

We often statically link 100 executables or more and I can envision  
two ways to speed it up.  One method is to link shared and the other  
is to use more processors at link time since some of our links take  
15 minutes or more.

Would this be a useful capability if I added the ability to specify  
the number of links on the bjam command line with a feature like  
concurrent-links=4?

-- Noel