how to compile with march=x86-64-v3 ?

[mabod]

I want to build my own cachyos kernel with march=x86-64-v3. How do I do that?

I was not able to figure out how to do that with _processor_opt and _use_auto_optimization.

[ptr1337]

https://github.com/CachyOS/linux-cachyos/blob/master/linux-cachyos/configure#L69

You can use the configure script and need to remove _use_auto_optimization

[mabod]

I did change the configure script and hardcoded GENERIC_CPU3.

But my intention was to solve this by just editing the PKGBUILD. This would be the ideal solution. I do not want to mess with all the other files.

linux-tkg for example offers an option like _processor_opt="generic_v3". This is a much more elegant solution from my point of view.

[ptr1337]

Yes, you can do the same here? Just put it into_processor_opt generic_v3 and remove the auto-cpu-optimization.

[mabod]

I do this:

export _processor_opt="generic_v3"
export _use_auto_optimization=""
export _HZ_ticks="300"
makepkg

And it does not work. The config is still with CONFIG_GENERIC_CPU=y

[mabod]

The PKGBUILD has the following code:

    if [ -n "$_processor_opt" ]; then
        MARCH="${_processor_opt^^}"
        MARCH2=M${MARCH}
        scripts/config -k -d CONFIG_GENERIC_CPU
        scripts/config -k -e CONFIG_${MARCH2}
    fi

That does not work if I want to configure march=x86-64-v3 because that needs:

scripts/config -k -e CONFIG_GENERIC_CPU3

But MARCH2 introduces an extra character 'M'

[mabod]

This is how I do it now:

# with -march=x86-64-v3
export _processor_opt="y"
export _use_auto_optimization=""
sed -i 's/MARCH2=.*/MARCH2=GENERIC_CPU3/' PKGBUILD

[ptr1337]

Yes, we will work on this.

[ptr1337]

Could you please retest?

[mabod]

It work fine. By setting

export _processor_opt="GENERIC_CPU3"
export _use_auto_optimization=""

I get -march=x86-64-v3