[Letux-kernel] compressing kernel

Andreas Kemnade andreas at kemnade.info
Sat Oct 26 20:11:23 CEST 2019


Hi Nikolaus,

On Sat, 26 Oct 2019 19:09:10 +0200
"H. Nikolaus Schaller" <hns at goldelico.com> wrote:

> Hi,
> 
> > Am 26.10.2019 um 16:11 schrieb Andreas Kemnade <andreas at kemnade.info>:
> > 
> > Hi,
> > 
> > I have just played around with compression options and found that
> > we are still  < 4MB with lzma  
> 
> Would be nice!
> 
> Although we have 6 MB in NAND for GTA04 and plenty of space on µSD
> for all others.

well, we are at >5MB, and there might be more stuff to be compiled
statically (if we want imx6sl* in. 
# CONFIG_SOC_IMX6SL is not set
# CONFIG_SOC_IMX6SLL is not set

> 
> > 
> > That can be switched by
> > # CONFIG_KERNEL_GZIP is not set
> > CONFIG_KERNEL_LZMA=y  
> 
> Yes, it is the default in omap2plus_defconfig AFAIK.
> 
And I booted omap2plus_defconfig several times.


> > Downside is a lot slower compression and a bit slower decompression
> > (still faster than bzip2).  
> 
> And that all our u-boot binaries do not understand it.
> 
It is not their business to uncompress it. The kernel extracts itself.
andi at aktux:~/gta04/gta04-kernel$ file ../5.4-rc1-letux/arch/arm/boot/uImage 
../5.4-rc1-letux/arch/arm/boot/uImage: u-boot legacy uImage, Linux-5.4.0-rc4-letux+, Linux/ARM, OS Kernel Image (Not compressed), 3892752 bytes, Sat Oct 26 10:20:31 2019, Load Address: 0x80008000, Entry Point: 0x80008000, Header CRC: 0xE7C5FDF5, Data CRC: 0x7032D32E
andi at aktux:~/gta04/gta04-kernel$ ls -l ../5.4-rc1-letux/arch/arm/boot/uImage
-rw-r--r-- 1 andi andi 3892816 Oct 26 12:20 ../5.4-rc1-letux/arch/arm/boot/uImage

Note: *not compressed*. Means that uboot does not do any decompression
itself.

> Unfortunately, the latest stuff is not always the best :(
> 
I do not see any problem in using it.

Regards,
Andreas


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