On Fri, Sep 18, 2026 at 04:27:39PM +0200, Manuel Ebner wrote: > Hi Lorenzo, > > On Thu, 2026-09-17 at 17:06 +0100, Lorenzo Stoakes (ARM) wrote: > > The gzip step of a kernel build is very lengthy, especially for larger > > builds such as allmodconfig. > > > > ... > > > > Whole build, 128-thread Threadripper 9980X, best of N runs: > > > > before after delta > > ------------------------------- > > x86 defconfig, touch mm/vma.c, gcc 7.7s 6.0s -1.7s (-22%) > > x86 defconfig, touch mm/vma.c, clang 6.9s 5.4s -1.5s (-21%) > > x86 defconfig, clean, gcc 28.2s 26.3s -1.8s (-6%) > > x86 defconfig, clean, clang 28.7s 27.2s -1.5s (-5%) > > x86 allmodconfig, touch mm/vma.c, gcc 23.7s 15.4s -8.3s (-35%) > > x86 allmodconfig, touch mm/vma.c, clang 22.5s 15.6s -7.0s (-31%) > > x86 allmodconfig, clean, gcc 294.1s 278.6s -15.5s (-5%) > > x86 allmodconfig, clean, clang 283.9s 266.8s -17.1s (-6%) > > That's good to hear.
:) > > > > Suggested-by: Kees Cook <[email protected]> > > Link: https://zlib.net/pigz/ > > Assisted-by: LLM > > Signed-off-by: Lorenzo Stoakes (ARM) <[email protected]> > > --- > > Documentation/kbuild/kbuild.rst | 17 +++++++++++++++++ > > Documentation/process/changes.rst | 8 ++++++++ > > Makefile | 5 ++++- > > kernel/Makefile | 6 +++++- > > scripts/Makefile.lib | 4 ++-- > > Please add a line to > scripts/ver_linux Ack, done for v4! > > > scripts/jobserver-exec | 3 ++- > > tools/lib/python/jobserver.py | 13 +++++++++++++ > > 7 files changed, 51 insertions(+), 5 deletions(-) > > > > diff --git a/Documentation/kbuild/kbuild.rst > > b/Documentation/kbuild/kbuild.rst > > index 5a9013bacfb7..e71a692a559a 100644 > > --- a/Documentation/kbuild/kbuild.rst > > +++ b/Documentation/kbuild/kbuild.rst > > @@ -110,6 +110,23 @@ HOSTLDLIBS > > ---------- > > Additional libraries to link against when building host programs. > > > > +KGZIP > > +----- > > +The gzip program used for compressed modules, packaging and the embedded > > Could you also add gzip to changes.rst and ver_linux while you are at it? > Rest looks good to me. I'd rather leave that out of this series tbh, if I listed it then I have to choose a minimum version that and feels out of scope. One for a follow-up? > Reviewed-by: Manuel Ebner <[email protected]> Thanks! > > Thanks > Manuel > > > +kernel configuration. Defaults to gzip. > > + > > +KPGZIP > > +------ > > +The gzip program used for the compressed kernel image. Defaults to pigz (a > > +parallel implementation of gzip), run under scripts/jobserver-exec so that > > it > > +uses the job slots make has free, if pigz is installed, otherwise to > > +``KGZIP``. Set ``KPGZIP=`` on the make command line to use another program. > > + > > +KBZIP2, KLZOP, LZMA, LZ4, XZ, ZSTD > > +---------------------------------- > > +The compressor programs for the other formats. Each defaults to the program > > +of the same name. > > + > > .. _userkbuildflags: > > > > USERCFLAGS > > diff --git a/Documentation/process/changes.rst > > b/Documentation/process/changes.rst > > index 0aa232b117b5..28f2ca63318e 100644 > > --- a/Documentation/process/changes.rst > > +++ b/Documentation/process/changes.rst > > @@ -55,6 +55,7 @@ nfs-utils 1.0.5 showmount > > --version > > + gzip > > > openssl & libcrypto 1.0.0 openssl version > > pahole 1.26 pahole --version > > pcmciautils 004 pccardctl -V > > +pigz (optional) 2.4 pigz --version > > PPP 2.4.0 pppd --version > > procps 3.2.0 ps --version > > Python 3.9.x python3 --version > > @@ -206,6 +207,13 @@ GNU AWK > > GNU AWK is needed if you want kernel builds to generate address range data > > for > > builtin modules (CONFIG_BUILTIN_MODULE_RANGES). > > > > +pigz (optional) > > +--------------- > > + > > +pigz is a parallel implementation of gzip. If it is installed the > > compressed > > +kernel image is produced with it rather than with gzip, see ``KPGZIP`` in > > +Documentation/kbuild/kbuild.rst. > > + > > System utilities > > **************** > > > > diff --git a/Makefile b/Makefile > > ... > -- Cheers, Lorenzo
