From: Junio C Hamano Date: Wed, 28 Jun 2006 21:24:37 GMT Subject: Re: [PATCH] Makefile: set USE_PIC on Linux x86_64 for linking with Git.pm Message-ID: <7vbqsdynvu.fsf@assigned-by-dhcp.cox.net> In-Reply-To: <20060628190814.GC5713@fiberbit.xs4all.nl> Marco Roeland writes: > Even for Linux someone mentioned that probably i386 is the exception in > _not_ needing the -fPIC linkage. It might even be specific to the Perl > "xs" implementation specifics? USE_PIC is for pleasing Perly git and nothing else right now. > So I should have added "Works for me (TM)"! ;-) That would have been more explicit way to tell me that this is a partial solution and I should solicit help from people on other platforms. By the way, I had an impression that compiling things with -fPIC when not necessary was generally a bad idea from performance point of view. If that is the case we might want to compile, under USE_PIC, everything with -fPIC in a separate area to compile and link with Git.xs, without affecting the C-only core code. I suspect this would largely depend on the architecture. I ran git-fsck-objects compiled with and without -fPIC (after "make clean" to rebuild everything) on a fully packed copy of the linux-2.6 repository on my x86_64 box, and did not see meaningful differences: : gitster; /usr/bin/time ../git.junio/git-fsck-objects-no-pic --full 109.71user 5.01system 1:54.89elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (14major+1834967minor)pagefaults 0swaps : gitster; /usr/bin/time ../git.junio/git-fsck-objects-with-pic --full 109.05user 4.97system 1:54.08elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (0major+1834981minor)pagefaults 0swaps : gitster;