Hello all, i am trying to install funtoo (again) on my PC. I have a doubt: which sub-arch to choose? I have a AMD FX-8150 cpu, so have I to dovnload stage3 for "generic_64" or "amd-k10"? what differences between them?
Another thing, when i compile kernel, in "processor type" section, have I to choose "opteron/k8..." choice or "generic x86_64"?
Thanks for your replies
welcome to the Funtoo community!
First: If you are in doubt, try generic. This will always do, even when another arch might result in a time gain of 60 seconds when compiling OpenOffice or such for ~20 Minutes ... it isn't that important really in my eyes.
But to answer your question as good as possible: I do not know for 100% myself. If someone else knows even better, please give your 2 ct's here.
I have a AMD FX-8150 cpu, so have I to dovnload stage3 for "generic_64" or "amd-k10"? what differences between them?
Please see Funtoo download guide: When you have a look in the x86-64bit - folder, there are "only" a limited pool of relevant sub-archs to choose from (neither atom nor intel apply when using AMD):
(My) Answer to "what to download": In Funtoo download guide amd64-k10 is described as
AMD Phenom, Phenom II and compatible, or higher
. So I think "amd64-k10" is the best non-customized choice available, currently.
(My) Answer to "What are the differences between them": First: As far as I know, you do not have to choose this at initial setup and are bound to this afterwards then forever. The main differences are that different/more specific CPU capabilities for GCC have been used to compile the binaries in it (like SSE, cache-sizes, etc.) and that these settings are set as default to be used when you build new packages on your own later. When you choose a sub-arch which is "too high" for the precessor you have, this might result in software which does not operate correctly on your system. But when you choose a sub-arch "too low" to fit your cpu, everything will run fine; but with further customization (which can be set later at anytime and the installed binaries can be rebuild with that settings) the binaries can make use of the advanced features the cpu supports and (possibly) run faster, but this gain is usually very minimalistic. That's why I'd suggest you to prefer "stability" to "speed" as long as you didn't found exact and well-tested hints to improve the arch settings, fitting exactly your arch.
I'd suggest to use the "amd64-k10" sub-arch and , when the install guide suggests the manipulation of /etc/portage/make.conf, to have a look at the very bottom entry of Gentoo wiki's page of Safe Cflags/AMD
The answer to the question what's the best to use when compiling a kernel is merely the same as to system wide optimization I just explained: Choose the one, fitting your current CPU best and give it a shot!