Re: [gentoo-user] make -j <n> for kernel builds?

[John Covici]

On Mon, 31 Oct 2016 18:33:44 -0400,
Alan McKinnon wrote:
>
> On 01/11/2016 00:27, John Covici wrote:
> > On Mon, 31 Oct 2016 18:06:07 -0400,
> > Alan McKinnon wrote:
> >>
> >> On 31/10/2016 23:57, John Covici wrote:
> >>> On Mon, 31 Oct 2016 13:37:50 -0400,
> >>> Meino.Cramer@×××.de wrote:
> >>>>
> >>>> Dale <rdalek1967@×××××.com> [16-10-31 18:36]:
> >>>>> Meino.Cramer@×××.de wrote:
> >>>>>> Hi,
> >>>>>>
> >>>>>> from ancient times ;) I remember, that it is not advisable
> >>>>>> to compile a linux kernel with more than one cpu core.
> >>>>>>
> >>>>>> Is that still true, or is it save to compile it with
> >>>>>> "all you can eat" ::)) ?
> >>>>>>
> >>>>>> Cheers
> >>>>>> Meino
> >>>>>>
> >>>>>>
> >>>>>
> >>>>> While I don't upgrade my kernel very often, since I don't reboot often
> >>>>> either, I've used -j 6 for my 4 core CPU for a long time.  I'm pretty
> >>>>> sure I've done that ever since I built this rig.  So far, no problems
> >>>>> that I have seen.
> >>>>>
> >>>>> Dale
> >>>>>
> >>>>> :-)  :-)
> >>>>>
> >>>>
> >>>> Great! Currently rebuilding the kernel with '-j7 ' :)
> >>>
> >>> I wonder, how does it make sure that a dependency is always compiled
> >>> before  what depends on it, so the link and all that works?
> >>>
> >>
> >> The kernel is special - it's a completely self-contained body of code
> >> with no external dependencies, so it is internally consistency almost as
> >> a matter of course.
> >>
> >> As for compiling the right things in the right order, the Makefiles take
> >> care of that just like all other software with a build system. How does
> >> the Makefile get made? Well, when you do make <something>config, you see
> >> all those deps like how iwlwifi depends on 80211 which depends on
> >> networking etc. That tells you the order things must be built in. Shove
> >> that into a Makefile maker, and voila, Bob's your auntie. Build issues
> >> tends to get fixed during the dev period so when Linux releases a kernel
> >> there's an excellent chance it will build correctly.
> >>
> >> FWIW, none of this is a specially difficult problem. It's the kind of
> >> thing I'd expect bright CS students to be able to do at the end of the
> >> first year
> >
> > OK, I will maybe try something, but I have had gentoo problems only
> > solved by -j1 due to such things, I guess.
> >
>
>
>
> With the kernel? Very very highly unlikely. If you had that problem,
> there is something wrong with your setup and I'd be very reluctant jump
> at the kernel Makefiles being the problem.
>
> Now if you said you had that problem with libreoffice, I'd agree 100%.
> The kernel? No.
>
>
> and btw, emerge problems that are solved using -j1 are
> a) not gentoo problems at all
> b) neither are they compiler problems
> c) they are always build problems caused by the package's own shitty
> build system and by upstream devs that never heard of this idea called
> "test your stuff to make sure it works in the real world"

I am sure you are correct, I have never tried this with the kernel, so
that will be an experiment for me.

Thanks.

-- 
Your life is like a penny.  You're going to lose it.  The question is:
How do
you spend it?

         John Covici
         covici@××××××××××.com