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
