Re: [master/kirkstone][PATCH 1/5] linux-bb.org: update to 5.10.162 and dedicated branches

[Denys Dmytriyenko <denis@denix.org>]

On Fri, Apr 07, 2023 at 03:50:43PM -0500, Robert Nelson wrote:
> On Fri, Apr 7, 2023 at 3:36 PM Denys Dmytriyenko <denis@denix.org> wrote:
> >
> > From: Denys Dmytriyenko <denys@konsulko.com>
> >
> > * Update both 32 and 64-bit trees to 5.10.162
> > * Switch from using a common branch that gets periodically rebased to using
> >   dedicated per-merge branches
> > * Patch 32-bit defconfig to use LZMA compression instead of LZO, that is
> >   being deprecated in OE-Core
> >
> > Cc: Robert Nelson <robertcnelson@gmail.com>
> > Signed-off-by: Denys Dmytriyenko <denys@konsulko.com>
> > ---
> >  ...h-default-kernel-compression-to-LZMA.patch | 30 +++++++++++++++++++
> >  .../recipes-kernel/linux/linux-bb.org_git.bb  | 18 ++++++-----
> >  2 files changed, 40 insertions(+), 8 deletions(-)
> >  create mode 100644 meta-ti-bsp/recipes-kernel/linux/linux-bb.org/0001-defconfig-switch-default-kernel-compression-to-LZMA.patch
> >
> > diff --git a/meta-ti-bsp/recipes-kernel/linux/linux-bb.org/0001-defconfig-switch-default-kernel-compression-to-LZMA.patch b/meta-ti-bsp/recipes-kernel/linux/linux-bb.org/0001-defconfig-switch-default-kernel-compression-to-LZMA.patch
> > new file mode 100644
> > index 00000000..f6bff39f
> > --- /dev/null
> > +++ b/meta-ti-bsp/recipes-kernel/linux/linux-bb.org/0001-defconfig-switch-default-kernel-compression-to-LZMA.patch
> > @@ -0,0 +1,30 @@
> > +From 0ccadc7a676341bbd66eb176308c7c59931e9dd2 Mon Sep 17 00:00:00 2001
> > +From: Denys Dmytriyenko <denys@konsulko.com>
> > +Date: Fri, 7 Apr 2023 01:44:56 +0000
> > +Subject: [PATCH] defconfig: switch default kernel compression to LZMA
> > +
> > +LZO compression and lzop tool haven't been maintained for long time and have
> > +been removed in recent versions of OE-Core, even though Debian may still use
> > +them. Switch to LZMA compression that is used by default in TI kernel config.
> > +
> > +Upstream-Status: Inappropriate [OE-specific]
> > +
> > +Signed-off-by: Denys Dmytriyenko <denys@konsulko.com>
> > +---
> > + arch/arm/configs/bb.org_defconfig | 2 +-
> > + 1 file changed, 1 insertion(+), 1 deletion(-)
> > +
> > +diff --git a/arch/arm/configs/bb.org_defconfig b/arch/arm/configs/bb.org_defconfig
> > +index 6bf0fb860683..7c035735172d 100644
> > +--- a/arch/arm/configs/bb.org_defconfig
> > ++++ b/arch/arm/configs/bb.org_defconfig
> > +@@ -1,5 +1,5 @@
> > + # CONFIG_LOCALVERSION_AUTO is not set
> > +-CONFIG_KERNEL_LZO=y
> > ++CONFIG_KERNEL_LZMA=y
> > + CONFIG_SYSVIPC=y
> > + CONFIG_POSIX_MQUEUE=y
> > + CONFIG_NO_HZ_IDLE=y
> 
> Oh! I didn't realize, lzo is in a sorry state.

Well, lzo is still kind of supported in OE-Core... But since lzop tool has 
been removed (actually, moved to supplemental meta-openembedded layer), you 
can't easily build lzo-compressed kernel w/o extra dependencies.


> Our only reason for using lzo over lzma, was purely a boot-up speed
> race. (Thinking with the am335x single core at 1Ghz..)
> 
> Does OE-Core have proper support for lz4 as a replacement? Or just in
> general lzma is the most recommended?

lzma, lz4, zstd are all supported, with zstd being the hot addition lately. 
Agree, lz4 may be the best choice for low-power devices like am335x...

https://indico.fnal.gov/event/16264/contributions/36466/attachments/22610/28037/Zstd__LZ4.pdf
https://linuxreviews.org/Comparison_of_Compression_Algorithms

-- 
Denys