#pepperidgefarmremembers
Might give it a try again.
I used Gentoo as my main OS for multiple years over a decade ago, installed it a couple of times, and helped with the localization of several documents, but I still remember the installation being basically the same as it is now.
I’m honestly wondering what is meant by this statement?
I failed at the chroot process at one point and ended up nuking a whole install.
I learned so much then though that has paid off in my career. Good times.
Incidentally, I had actually picked gentoo because the forums looked fantastic... My first linux attempt was with suse, but all the "interesting" answers were in German. So next time I tried the one with the liveliest forums. Turns out the forums were lively for a some of the wrong reasons (everything was hard), but the people were the right combination of friendly and incredibly helpful and knowledgeable. I learned a huge amount from the process and the people. Though, indeed, the whole from source distro thing was foolish, in retrospect.
Gentoo will forever be my "uphill through the snow both ways" story.
I didn't have cross-compiling set up yet, and I unwisely decided to install X. And Gnome. And Open Office.
It compiled for days.
(and, yes, I do remember waiting a full day for KDE to compile)
https://web.archive.org/web/20080704112619/http://funroll-lo...
Actually, probably quite the contrary. All x86-64 chips are required to support SSE2, which lets you use SSE for floating-point instead of x87 floating-point, which is a big speed win. But the newer extensions are specialized SSE instructions, which generally require manual use of instructions to utilize; specialized crypto instructions, which definitely require manual use; and AVX instructions, which doubles the width of vectors you can use. The first two is not going to be improved with -march; the code that uses it is almost certainly going to be compiled in a way that lets it dynamically use these instructions when available.
As for vectorized code that could use AVX instead, it's dubious how much of an effect it would have, since the biggest improvement in vectorization will be enabled with the 128-bit vectors, with 256-bit vectors offering at most a 2x speedup in the vectorized code, the effect being reduced by some code only being 128-bit-vectorizable (and not receiving any speedup), and also by Amdahl's Law reducing the benefit of further speedups in that code. Furthermore, vectorization tends to be much less relevant in the "integer" code that is typical of most consumer software, outside of a few hot loops that are already manually specified as above.
For hot kernels (say, memcpy), it is definitely the case that many projects have implementations of several different varieties of these, and use the version best suited for your current architecture. See https://sourceware.org/git/?p=glibc.git;a=tree;f=sysdeps/x86... for the different variants of common functions in glibc.
[0] Which is the point of Gentoo, after all. It's what made it a lot better than LFS/BFS. You get everything from source with little effort. 17 years later, I'm still using Gentoo. Nothing like it.