Re: [gentoo-user] Gentoo's advantage: "optimized for your system" -- huh?

[Volker Armin Hemmann <volkerarmin@googlemail.com>]

On Dienstag 03 Februar 2009, Grant Edwards wrote:
> Whenever I see a write-up of Gentoo, it's describe as a system
> similar to BSD "ports" where you build packages from source.
> The main benefit claimed for this approach is that you get
> better performance because all executables are optimized for
> exactly the right instruction set.
>
> Where did that bit of apocrypha come from, and why is it
> parroted by so many people?

because it was true in the beginning, when most distris were still built for 
386 and the difference of an optimized built was that you could watch dvd 
movies without hangs and frame loss.

It is still true to a certain degree today - code compiled for 386 runs much 
slower than code compiled for core2 - on a core2. But on todays overpowered 
cpus you don't see it as prominent as back on k6-2 400 or p3 650 ....


> AFAICT, the "performance" benefit due to compiler optimization
> is practically nil in real-world usage.

nope, they are there. But compiler optimiziations are a very delicate thing. 
You can't just throw funroll-all-loops into make.conf and think that was it. 
And for a general set, march is the most important one. It does do a lot of 
good - the rest is just minor at best.