svn commit: r222980 - in head/sys: amd64/conf i386/conf

[Ulrich Spörlein]

On Sat, 11.06.2011 at 13:55:15 -0700, Doug Barton wrote:
> On 6/11/2011 1:02 PM, Warner Losh wrote:
> >
> > On Jun 11, 2011, at 12:17 PM, Doug Barton wrote:
> >
> >> On 6/11/2011 6:07 AM, Robert Watson wrote:
> >>> To me, this seems like the wrong direction.  Over the last decade, we've
> >>> been trying to move away from conditional compilation of features to
> >>> having them be loadable as modules.
> >>
> >> FWIW, I agree. I'm wondering though, is there still a performance penalty for modules? My understanding in the past was that there is, although for most use cases it's in the statistical noise. Is that still true?
> >
> > At run time, I believe that's true.  At load time, lots of modules can take a few seconds longer.
> 
> I have 3 or 4 modules loaded via loader.conf at boot time. They take at 
> least 2 seconds each. IMO loading everything via loader.conf would slow 
> the boot so much as to be a non-starter.
> 
> OTOH, I could imagine an rc.d script that depends on mountcritlocal that 
> could load a list of modules. Unless I'm missing something that would be 
> several times faster.

I suspect this is your BIOS' fault. I load 22 modules via loader.conf
and the loader takes 2, at most 3, seconds to load them all (next to the
kernel). This is true for all machines that I own/owned.

As you can guess, I'm very much in favour of moving modules from GENERIC
to loader.conf ...

Uli