Re: [PATCH] kbuild: add variables for compression tools

[Sedat Dilek <sedat.dilek@gmail.com>]

On Thu, Jun 4, 2020 at 7:01 PM Denis Efremov <efremov@linux.com> wrote:
>
> >
> > me and other people use "support for ZSTD-compressed kernel and
> > initramfs" for a long time successfully.
> >
> > I have modified Debian's initramfs-tools package to support creating
> > such an initrd.img and boot it successfully.
> > See Debian Bug #955469.
> >
> > There is a pull-request sent out to integrate into Linus tree.
> >
> > Some numbers from Nick Terell in his pull-request:
> > "
> > The zstd compressed kernel is smaller than the gzip compressed kernel but larger
> > than the xz or lzma compressed kernels, and it decompresses faster than
> > everything except lz4. See the table below for the measurement of an x86_64
> > kernel ordered by compressed size:
> >
> > algo size
> > xz   6,509,792
> > lzma 6,856,576
> > zstd 7,399,157
> > gzip 8,522,527
> > bzip 8,629,603
> > lzo 9,808,035
> > lz4 10,705,570
> > none 32,565,672
> > "
> >
> > More numbers in [0].
> >
> > Hope this helps you to position the zstd algo.
>
> Well, I didn't know that it's already implemented.
>
> My patch simply adds variables like GZIP, BZIP2, etc to the top makefile.
> Unfortunately there is no ZSTD in kernel now. Maybe it's in the linux-next?
> I can't see it. If my patch will be accepted to the mainline then it will
> be reasonable to add ZSTD var in makefiles as soon as zstd compression
> will be merged.
>

No, it was not merged anywhere AFAICS.

If you want to test please pull from [1].
I am using it on top of Linux v5.7.

- Sedat -

[1] https://github.com/terrelln/linux/commits/zstd-v5