We are using a standard distro of gmake 4.1 on RH 6.4. We have a fairly well structured makefile system that leverages the ACE make framework. A linear build (-j1) is about 3 hours. Running a parallel build that builds leaf nodes (libraries) in parallel is about 1 hour. So far so good.
But when I try to build across makefiles in parallel then I see two different things: 1) If I turn on any sort of output sync it gets dramatically slower. Sometimes slower than our -j1 time! 2) Even with output sync turned completely off there is no meaningful improvement over a parallel build of just the leaves. I am reasonably certain that I am actually seeing parallel build behavior since I had to fix a handful of additional dependency issues to get it to build. Also reasonably certain that the build is not doing different things since the count of compiler invocations matches. Looking at 'top' during the "highly parallelized" runs shows the system essentially idle. -- View this message in context: http://gnu-make.2324884.n4.nabble.com/Parallel-builds-across-makefiles-tp17266.html Sent from the Gnu - Make - Bugs mailing list archive at Nabble.com. _______________________________________________ Bug-make mailing list Bug-make@gnu.org https://lists.gnu.org/mailman/listinfo/bug-make
