Re: [PATCH v2] use xz and gzip on host (outside chroot)

[Anton Mikanovich <amikan@ilbers.de>]

08.08.2022 10:36, Felix Moessbauer wrote:
> From: Adriaan Schmidt <adriaan.schmidt@siemens.com>
>
> This patch significantly speeds up the final image compression
> as the compression itself is no longer emulated.
>
> For gzip, no additional dep has to be installed on the system,
> for xz the xz-utils package has to be installed but this will
> be required from bitbake 2.0 on anyways.
>
> Signed-off-by: Adriaan Schmidt <adriaan.schmidt@siemens.com>
> Acked-by: Felix Moessbauer <felix.moessbauer@siemens.com>

Hello,

I've made some investigations to collect compression speed statistics on
qemuarm64-bullseye Isar target with 490Mb rootfs. Here are the results:

XZ:
Buildchroot xz (QEMU):   45.305s
Host xz:                 18.783s

GZIP:
Buildchroot gzip (QEMU):   4m30.155s
Host gzip:                 1m30.135s
Buildchroot gzip (native): 1m27.162s

Buildchroot pigz (QEMU):     32.265s
Host pigz:                   13.131s

So it looks reasonable to use native compression and we really need to think
about removing ISAR_CROSS_COMPILE="0" for imager.
We also can try to use parallelized pigz for gzip compression.