Yet more "preloading"

[Lubos Lunak]

On Thursday 18 of March 2004 18:14, Andrew Morton wrote:
> Oswald Buddenhagen <ossi at kde.org> wrote:
> > i'm not sure i like the "statistical auto-configuration" for kdm you
> >  described.
> >  however, this gave me an Absolutely Brilliant Idea (TM): this whole
> >  problem could/should be solved in a generic way with kernel support: the
> >  kernel only needs to create a file access log of the boot process. on
> >  subsequent boots, preloading would be initiated based on this data. of
> >  course things become fun at the point the boot process branches
> >  (different sessions are choosen); this could be either auto-detected
> >  with "life analysis" of the current boot process, or by hinting from
> >  user space (hello ?dm) - the latter sounds less like a hack, but
> >  requires support in many programs.
> >  does this sound like a plan? andrew?
>
> I wrote a thingy to do that once.  It is described in the discussion at
> http://kerneltrap.org/node/view/2157, which is worth a read.

 That discussion seems to lack any conclusion :-/.

"So it's all an attempt to optimise the boot-time I/O patterns. It was pretty 
much a waste of time, gaining only 10% or so, from memory. You could get just 
as much or more speedup from simply launching all the initscripts in 
parallel, although this did tend to break stuff."

 10% of what exactly? Was that measured as time LILO->KDE, LILO->text, 
text->KDE or something else? Initscripts usually are anything but fast, and 
if you managed to make startup 10% faster with all those init.d scripts 
sleeping and making the machine do nothing, then the speedup would be 
noticeably better with initscripts that actually care about startup time (I 
think there are some attempts to make them parallel these days). Moreover, I 
have no clue what your code does, but even if it just reduces KDE startup 
time by 10%, it's still worth it.

 I'll give the fdboot sources a try (I need kernel recompile :-/). Could you 
please explain in short what it does (or, to be more precise, how we 
could/should use it)?

-- 
Lubos Lunak
KDE developer
---------------------------------------------------------------------
SuSE CR, s.r.o.  e-mail: l.lunak at suse.cz , l.lunak at kde.org
Drahobejlova 27  tel: +420 2 9654 2373
190 00 Praha 9   fax: +420 2 9654 2374
Czech Republic   http://www.suse.cz/