Re: [ptxdist] Generation of additional xz rootfs archive

[Michael Olbrich <m.olbrich@pengutronix.de>]

Hi,

On Wed, Nov 11, 2015 at 02:06:36PM +0000, Bruno Thomsen wrote:
> I am currently looking into the possibility of adding ptxdist generation of
> a xz rootfs archive, as I thought the feature might be useful for others as
> well.
> Should it be added as a new script like ptxd_make_image_archive_impl
> (image/archive) or implemented in C inside genimage (image/genimage)?
> 
> The goal is to optimize our firmware upgrade image size.
> This could be done by switching from gz to xz rootfs which reduces size with
> approx 35%.
> The production firmware will still be using a gz rootfs archive.
> 
> I basically want to do the following command:
> gzip -d < root.tgz | xz -9e > root.tar.xz
> 
> 
> Compression level should be configurable so it can be adjusted to target
> memory size.
> Memory usage is approx 65MB during extraction of a -9 archive on an i.MX28
> processor when using xz from Busybox.
> In my testing the CompMem/DecMem listed in "man xz" seems to be valid for
> embedded ARM Linux systems as well.
> 
> 
> Otherwise this will just end as even more clutter in our custom build script
> wrapper around ptxdist :)

This can be easily done in PTXdist. You just need to use the 'new' image
mechanism:

$ ptxdist newpackage image-genimage

 - remove the .config file
 - select IMAGE_ROOT_TGZ in the .in file and remove select for genimage.
 - remove the _FILES and __CONFIG line the .make file
 - replace the image/genimage line with your recompression command.

We cannot define every possible image within upstream PTXdist. That's why I
created the new image mechanism to make it easy to add new images in a BSP.

Michael

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