kernel comparison
#1
I'm sure this has been asked before, but I can't seem to find it.  What are the differences between ayufan and mrfixit's kernels?
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#2
Nobody has written a comprehensive guide but you may be interested in looking at the git commit logs for the various projects

https://github.com/mrfixit2001/rockchip-...elease-4.4

https://github.com/mrfixit2001/debian_bu...its/master

https://github.com/ayufan-rock64/linux-b...its/master

https://github.com/ayufan-rock64/linux-k...se-4.4.184
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#3
What are YOU looking for?
Me, an aarch64 development system on which I can test the NEON extended instructions.
So, I want to see "neon" in /proc/cpuinfo
Also since the RK3399 has six cores, 4x A53 and 2x A72, I want to see that in /proc/cpuinfo.
AND since mainline Linux is at kernel 5.2.x and GCC is at 8.3.x, them too.
Mrfixit and Ayufan are doing kernel 4.4.xx and GCC Ver 7.3.
Manjaro is so far the best with kernel 5.1.x and GCC 8.2.x (an Arch spin off)
DietPi on RockPro64 Kernel 4.4.178, no neon in /proc/cpuinfo all exe's are ELF 64-bit LSB shared object, ARM aarch64
Ubuntu 18.04.2 LTS, kernel 4.4.167 No NEON in /proc/cpuinfo, gcc Ver 7.4.0 creates 64bit exe files
Debian, kernel from MrFixIt.
NetBSD, works but without GUI development libraries, way too hard to get my app going. NetBSD needs a repository for arm64, they are working on it.
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#4
Hello eard5849,
(07-10-2019, 05:49 AM)beard5849 Wrote: Me, an aarch64 development system on which I can test the NEON extended instructions.
So, I want to see "neon" in /proc/cpuinfo
see  bellow the links to ARM documentation..
Its related to NEON in ARMv7-A and ARMv7-R,
But maybe same behaviour( even though that there are changes between ARMv7 and ARMv8 )..

Sections 2.1.8 and 2.1.9:
NEON

Quote:A stock kernel is the kernel released by Linux at www.kernel.org, without modification.

If you use a Linux stock kernel to run your application, there is no need to manually enable the NEON unit.
The kernel automatically enables the NEON unit when it encounters the first NEON instruction.

If the NEON unit is disabled and the application tries to execute a NEON instruction, it throws an Undefined Instruction exception.

The kernel uses this exception to enable the NEON unit and then executes the NEON instruction.

The NEON unit remains enabled until there is a context switch.
When a context switch is required, the kernel might disable the NEON unit to save time and power.


Verify:
Code:
[email protected]:~# zcat /proc/config.gz | grep NEON
CONFIG_KERNEL_MODE_NEON=y

(07-10-2019, 05:49 AM)beard5849 Wrote: Also since the RK3399 has six cores, 4x A53 and 2x A72, I want to see that in /proc/cpuinfo.


I see that in '/proc/cpuinfo'
Code:
[email protected]:~# cat /proc/cpuinfo
processor : 0
BogoMIPS : 48.00
Features : fp asimd evtstrm aes pmull sha1 sha2 crc32
CPU implementer : 0x41
CPU architecture: 8
CPU variant : 0x0
CPU part : 0xd03
CPU revision : 4

processor : 1
BogoMIPS : 48.00
Features : fp asimd evtstrm aes pmull sha1 sha2 crc32
CPU implementer : 0x41
CPU architecture: 8
CPU variant : 0x0
CPU part : 0xd03
CPU revision : 4

processor : 2
BogoMIPS : 48.00
Features : fp asimd evtstrm aes pmull sha1 sha2 crc32
CPU implementer : 0x41
CPU architecture: 8
CPU variant : 0x0
CPU part : 0xd03
CPU revision : 4

processor : 3
BogoMIPS : 48.00
Features : fp asimd evtstrm aes pmull sha1 sha2 crc32
CPU implementer : 0x41
CPU architecture: 8
CPU variant : 0x0
CPU part : 0xd03
CPU revision : 4

processor : 4
BogoMIPS : 48.00
Features : fp asimd evtstrm aes pmull sha1 sha2 crc32
CPU implementer : 0x41
CPU architecture: 8
CPU variant : 0x0
CPU part : 0xd08
CPU revision : 2

processor : 5
BogoMIPS : 48.00
Features : fp asimd evtstrm aes pmull sha1 sha2 crc32
CPU implementer : 0x41
CPU architecture: 8
CPU variant : 0x0
CPU part : 0xd08
CPU revision : 2

Serial : 0000000000000000

[email protected]:~# pwd
/root
[email protected]:~# git clone --branch master https://github.com/tuxd3v/tools.git && cd tools
Cloning into 'tools'...
remote: Enumerating objects: 44, done.
remote: Counting objects: 100% (44/44), done.
remote: Compressing objects: 100% (34/34), done.
remote: Total 44 (delta 10), reused 42 (delta 8), pack-reused 0
Unpacking objects: 100% (44/44), done.
[email protected]:~/tools# ./aarch mtune

cortex-a72.cortex-a53

It is reported correctly

Regards,
tux
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