> Sent: Saturday, January 04, 2025 at 7:12 PM
> From: "Jeffrey Walton" <noloa...@gmail.com>
> To: poc...@homemail.com
> Cc: "debian-user" <debian-user@lists.debian.org>
> Subject: Re: debian kernel compiler
>
> On Sat, Jan 4, 2025 at 4:17 PM <poc...@homemail.com> wrote:
> >
> > > Sent: Saturday, January 04, 2025 at 11:54 AM
> > > From: "Lee" <ler...@gmail.com>
> > > To: "Franco Martelli" <martelli...@gmail.com>
> > > Cc: debian-user@lists.debian.org
> > > Subject: Re: debian kernel compiler
> > >
> > > On Sat, Jan 4, 2025 at 7:52 AM Franco Martelli wrote:
> > > >
> > > > On 02/01/25 at 12:53, Istvan Toth wrote:
> > > > > amd 5700G cpu
> > > >
> > > > If you are new to kernel compiling maybe you don't know that you can
> > > > optimize the kernel for your specific CPU architecture, if you are using
> > > > the GCC compiler:
> > > >
> > > > first make a backup copy of the Makefile:
> > > > $ cd linux-source-6.1
> > > > $ cp arch/x86/Makefile arch/x86/Makefile.backup
> > > >
> > > > then edit "arch/x86/Makefile":
> > > > $ cd linux-source-6.1
> > > > $ vi arch/x86/Makefile
> > > >
> > > > at line 152 change:
> > > > cflags-$(CONFIG_MK8) += -march=k8
> > > > to
> > > > cflags-$(CONFIG_MK8) += -march=znver3
> > > > and below at line 159 change
> > > > rustflags-$(CONFIG_MK8) += -Ctarget-cpu=k8
> > > > to
> > > > rustflags-$(CONFIG_MK8) += -Ctarget-cpu=znver3
> > > >
> > > > save and exit vim. "znver3" is the GCC's switch for the µarch of your
> > > > GPU.
> > >
> > > GPU or central processing unit?
> > >
> > > As long as you're not cross-compiling, how is march=znver3 better than
> > > march=native ?
> > >
> > > On my machine, 'man gcc' has the "znver1" and "znver2" strings, but no
> > > "znver3" so it seems like "march=native" would be more correct.. or
> > > at least less chances of an error.
> > > ... assuming there are no drawbacks to using "march=native".
> >
> > As someone that has compiled many a kernel on different platforms over 30
> > years......
> >
> > gcc has a facility to interrogate the system it is on, it will tell you
> > what is available on the platform hardware and flag wise.
> >
> > You should use that.
>
> The option to compile for "this machine" or "compiling machine" is
> -march=native. It should be added to CFLAGS and CXXFLAGS, assuming GNU
> makefile rules.
>
> The native option is available on certain targets. See, for example,
> <https://gcc.gnu.org/onlinedocs/gcc/x86-Options.html>.
>
> Jeff
30 years of building custom linux systems on multiple platforms says no.
That will fail on many platforms.
Again the correct way is as I stated above/previously
