Re: [gentoo-user] upgrading from kernel 2.6.24-rc6 to latest kernel

[Alan McKinnon]

On Monday 18 May 2009 19:59:14 William Hubbs wrote:
> On Mon, May 18, 2009 at 07:39:48PM +0200, Alan McKinnon wrote:
> > On Monday 18 May 2009 19:12:22 William Hubbs wrote:
> > > Another difference is that, since you are compiling everything from
> > > source, with the correct CFLAGS and CXXFLAGS settings in make.conf, you
> > > can optimize the binaries you produce to take full advantage of your
> > > processor, which you can't do on a binary distro since everything is
> > > already compiled for you.
> >
> > Another word:
> >
> > That's ricing.
> >
> > Ok, that's two words. You get the idea.
>
>  Actually, I don't, because I don't know what you mean.  I was just
>  pointing out something about gentoo which  I think is different from a
>  binary distribution.  I don't know how much of a difference it makes,
>  but it is a feature they don't have.

The cases where one really does need to optimize the compiler for your cpu are 
very rare, and only really apply to old hardware. Back in the day they 
performed fine, but code available today tends to do more (keeping pace with 
cpu capability) so you need to tweak things to extract the best performance.

If using current packages on current hardware, the benefit is questionable and 
users are highly unlikely to notice much difference between good old i686 and 
-O9. With some apps it does make a difference - extensive floating point ops 
comes to mind - and one should take advantage of those cases. However, looking 
into the ebuilds of such packages usually reveals that, if the maintainer is 
any good, those optimizations are already present in the ebuild.

Years ago Gentoo had a problem with fanatical moronic users claiming their 
machines performed a brazillion time faster with -O9 and other such nonsense. 
This is called "ricing" - a word play on young Japanese males modifying 
Subarus for "performance" that actually reduces performance. Ever seen a 
Subaru with a gigantic whale-tail rear spoiler? That's ricing. These Gentoo 
users seem to have gone away to wherever the current fashion fad is. For a 
while they infested Ubuntu. $DEITY only knows where they are now, maybe 
they're using MacOS and annoying Steve

Actual benchmarks should that ricing does nothing beneficial for the average 
ricer.

Genuine analysis of Gentoo machines admined by someone who knows how to do it 
should that the machine can easily have only the features and software on it 
that the admin say it should have. Like LDAP - not everyone needs it. On a 
binary distro, if the maintainer supports it you usually get it too whether 
you like it or not. With Gentoo, USE is your friend. And this is gentoo's 
greatest strength - the ability to build something much closer to what you 
really want than is possible with a binary distro.

-- 
alan dot mckinnon at gmail dot com