Messages in this thread | | | From | Keith Owens <> | Subject | Re: kbuild 2.5 is ready for inclusion in the 2.5 kernel | Date | Fri, 03 May 2002 22:07:14 +1000 |
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On Fri, 3 May 2002 01:33:34 -0700 (PDT), Vikram <vvikram@stanford.edu> wrote: ><snip> >ccache is a compiler cache. It acts as a caching pre-processor to C/C++ >compilers, using the -E compiler switch and a hash to detect when a >compilation can be satisfied from cache. This often results in a 5 to 10 >times speedup in common compilations ></snip> > >http://ccache.samba.org/
Firstly kbuild 2.5 removes the need to make clean or make mrproper for most compilations. You need to make mrproper when changing to a new architecture in the same directory (it is much better to use a separate object directory for each architecture), but apart from that you should not need to make clean or mrproper. IMNSHO having to issue make clean is a sign that your build system is broken, relying on human intervention in an automated build is falt out wrong. Automatic detection of an arch switch is on the enhancement list for kbuild 2.5.
Secondly kbuild 2.5 keeps objects that were built but are not currently selected, it just does not link or install them. Build a kernel, disable a set of drivers, build the kernel and it will just bump the version number and relink vmlinux. Enable the drivers again, kbuild 2.5 does not need to compile them, they are still there, it just bumps the version number and relinks vmlinux. Same with installing modules. Various .tmp files list the objects and modules required for the current .config.
So kbuild 2.5 removes the need to make clean after patches, changing configs, etc. It gets it right without human intervention.
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