I think you're misreading the documentation. There are two ways to "parallel compile":
1) Make -j2 will try to compile several .c files from one package at a time, if it can find 2 files with no dependencies. 2) Users could in theory try to compile two packages in parallel. Eg: "make glibc & make gcc" The documentation encourages you to do the first, but not the second. Sent on the TELUS Mobility network with BlackBerry -----Original Message----- From: littlebat <[email protected]> Sender: [email protected] Date: Wed, 7 Jul 2010 19:10:57 To: <[email protected]> Reply-To: LFS Support List <[email protected]> Subject: need an accurate answer: can we build LFS with parallel compiling? Hi, I am learning LFS BOOK 6.6. I have built all the packages successfully with parallel compiling (I set an environment "export MAKEFLAGS='j -2'" for user "lfs" ) according to the instruction in "4.5. About SBUs" as book says: <quote> For many modern systems with multiple processors (or cores) the compilation time for a package can be reduced by performing a "parallel make" by either setting an environment variable or telling the make program how many processors are available. </quote> >From my understanding, LFS BOOK 6.6 is implicit to say we can always use MAKEFLAGS='-j 2' or make -j2 to reduce compiling time when using a double cores CPU. If we run into a problem with a build step, revert back to a single processor build to properly analyze the error messages. But, when I read "6.1. Introduction", the book says: <quote> For the same reason, do not compile packages in parallel. Compiling in parallel may save time (especially on dual-CPU machines), but it could result in a program containing a hard-wired path to /tools, which will cause the program to stop working when that directory is removed. </quote> So, I need some accurate answers: 1, Can we build LFS with parallel compiling through the book? 2, Can we build Chapter 5 with parallel compiling but do not use parallel compiling in the rest Chapters (includes Chapter 6 and Chapter 8)? 3, I have finished building Chapter 5 with parallel compiling, if I need rebuild all Chapter 5 without parallel compiling again as section "6.1. Introduction" says? I have also had a glance at a hint that was written at 2004: How to build LFS using multiple compiler instances. http://www.linuxfromscratch.org/hints/downloads/files/parallelcompiling.txt -- littlebat -- http://linuxfromscratch.org/mailman/listinfo/lfs-support FAQ: http://www.linuxfromscratch.org/lfs/faq.html Unsubscribe: See the above information page -- http://linuxfromscratch.org/mailman/listinfo/lfs-support FAQ: http://www.linuxfromscratch.org/lfs/faq.html Unsubscribe: See the above information page
