On Thu, 27 Dec 2001 17:47:23 -0800, Larry McVoy <[EMAIL PROTECTED]> wrote: >On Fri, Dec 28, 2001 at 12:41:48PM +1100, Keith Owens wrote: >> On Thu, 27 Dec 2001 17:37:39 -0800, >> Larry McVoy <[EMAIL PROTECTED]> wrote: >> >A couple of questions: >> > >> >a) will 2.5 be as fast as the current system? Faster? >> >> At the moment kbuild 2.5 ranges from 10% faster on small builds to 100% >> slower on a full kernel build. > >I don't understand why it would be slower. Maybe I'm clueless but I thought >you were moving more towards a single makefile system
It uses a single generated Makefile, that is not the problem. The slow code is extracting the dependencies. Unlike the broken make dep, kbuild 2.5 extracts accurate dependencies by using the -MD option of cpp and post processing the cpp list. The post processing code is slow because the current design requires every compile to read a complete list of all the files, giving O(n^2) effects. Mark 2 of the core code will use a shared database with concurrent update so post processing is limited to looking up just the required files, instead of reading the complete list every time. _______________________________________________ kbuild-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/kbuild-devel
