[nzlug] Kernel this, Kernel that

[Glenn Enright]

On Tuesday 26 September 2006 17:02, Dirk Pilat wrote:
> Hi all,
>
> after another recent fruitless attempt to install Gentoo on one of my
> machines (I must be a closet masochist) and then putting Ubuntu on
> it, I was thinking about precompiled against self-compiled kernels,
> so here's the question:
>
> a) does in the time and age of Core Duo (and soon quadro) CPUs it
> really matter so much to self compile your kernel?

I have a mate who has been working on building a CoreDuo box, and he has 
also said its is not simple. My guess is that if your distro of choice 
has a precompiled kernel that works then its all good. The point of 
being able to 'roll your own' is really that you can slim down the 
kernel config to match your system more closely, which *may* mean 
better performance and/or security. 

Of course if your kernel doesnt work out of the box for XYZ hardware, 
then being able to build in support for XYZ is a bonus :). 

I'm a gentoo user from way back, and one of the things I enjoy most 
about using this distro is the empowerment to hack on system level 
stuff like kernel builds. Its not really an ideal distro for busy or 
non-hacker type personalities tho. All IMHO.

> b) what kind of advantages has a processor specific (i.e. K7) Kernel
> compared to a generic i386 kernel? Is there really a significant
> speed boost?

Probably not for most things, but its difficult to say without having 
something to compare to. Benchmarks are relative, both to system and 
purpose. 

For instance I recently (2.6.18) did a comparison between builds for a 
Pentuim4 and i386. The P4 code was bigger (~30K). Bigger code means 
more work for the VM system to load and access, but it may have run 
faster overall by using alternative instruction paths.

-- 
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