On 2014-07-30 01:11, Andi Kleen wrote: > From: Andi Kleen <ak@xxxxxxxxxxxxxxx> > > This is an alternative approach to lower the overhead of debug info > (as we discussed a few days ago) > > gcc 4.7+ and newer binutils have a new "split debug info" debug info > model where the debug info is only written once into central ".dwo" files. > > This avoids having to copy it around multiple times, from the object > files to the final executable. It lowers the disk space > requirements. In addition it defaults to compressed debug data. > > More details here: http://gcc.gnu.org/wiki/DebugFission > > This patch adds a new option to enable it. It has to be an option, > because it'll undoubtedly break everyone's debuginfo packaging scheme. > gdb/objdump/etc. all still work, if you have new enough versions. > > I don't see big compile wins (maybe a second or two faster or so), but the > object dirs with debuginfo get significantly smaller. My standard kernel > config (slightly bigger than defconfig) shrinks from 2.9G disk space > to 1.1G objdir (with non reduced debuginfo). I presume if you are IO limited > the compile time difference will be larger. > > Only problem I've seen so far is that it doesn't play well with older > versions of ccache (apparently fixed, see > https://bugzilla.samba.org/show_bug.cgi?id=10005) The failure mode with ccache is that the *.dwo files are not stored, but the build proceeds, right? This is at least what I'm seeing. I'm just wondering if the config option should be inverted to make all{yes,mod}config builds happy. But it's probably not necessary if the build passes. Thanks, Michal -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
