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

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

[Meino.Cramer]

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

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

[Dutch Ingraham]

On Mon, Oct 31, 2016 at 06:06:45PM +0100, Meino.Cramer@gmx.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" ::)) ?

That must be very ancient.  I've been following this [1] for over three years
without problems.

[1] https://wiki.gentoo.org/wiki/Kernel/Configuration#Build

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

[Dale]

Meino.Cramer@gmx.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

:-)  :-) 

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

[Hunter Jozwiak]

-----Original Message-----
From: Meino.Cramer@gmx.de [mailto:Meino.Cramer@gmx.de] 
Sent: Monday, October 31, 2016 13:07
To: Gentoo <gentoo-user@lists.gentoo.org>
Subject: [gentoo-user] make -j <n> for kernel builds?

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


I was wondering the same thing, as when I tried to compile my kernel it
panicked at boot; though this was probably my inexperience with building
them.


---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

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

[Meino.Cramer]

Dale <rdalek1967@gmail.com> [16-10-31 18:36]:
> Meino.Cramer@gmx.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 ' :)

Cheers
Meino

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

[Daniel Frey]

On 10/31/2016 10:35 AM, Dale wrote:
> Meino.Cramer@gmx.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
> 
> :-)  :-) 
> 

Not too long ago I ran -j33 on a new server at work, and built a kernel
in 47 seconds. I booted from that kernel and it worked fine.

Sometimes I forget to pass the -j parameter though at home. Then wonder
why it takes a while...

Dan

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

[Meino.Cramer]

Hunter Jozwiak <hunter.t.joz@gmail.com> [16-10-31 18:48]:
> 
> 
> -----Original Message-----
> From: Meino.Cramer@gmx.de [mailto:Meino.Cramer@gmx.de] 
> Sent: Monday, October 31, 2016 13:07
> To: Gentoo <gentoo-user@lists.gentoo.org>
> Subject: [gentoo-user] make -j <n> for kernel builds?
> 
> 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
> 
> 
> I was wondering the same thing, as when I tried to compile my kernel it
> panicked at boot; though this was probably my inexperience with building
> them.
> 
> 
> ---
> This email has been checked for viruses by Avast antivirus software.
> https://www.avast.com/antivirus
> 
> 

Now I am currently running my freshly booted, "fast compiled" kernel ---
currently no problems.

(vanilla 4.8.6)

Cheers
Meino

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

[John Covici]

On Mon, 31 Oct 2016 13:37:50 -0400,
Meino.Cramer@gmx.de wrote:
> 
> Dale <rdalek1967@gmail.com> [16-10-31 18:36]:
> > Meino.Cramer@gmx.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?

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

         John Covici
         covici@ccs.covici.com

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

[Alan McKinnon]

On 31/10/2016 23:57, John Covici wrote:
> On Mon, 31 Oct 2016 13:37:50 -0400,
> Meino.Cramer@gmx.de wrote:
>>
>> Dale <rdalek1967@gmail.com> [16-10-31 18:36]:
>>> Meino.Cramer@gmx.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



-- 
Alan McKinnon
alan.mckinnon@gmail.com

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

[John Covici]

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@gmx.de wrote:
> >>
> >> Dale <rdalek1967@gmail.com> [16-10-31 18:36]:
> >>> Meino.Cramer@gmx.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.

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

         John Covici
         covici@ccs.covici.com

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

[Alan McKinnon]

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@gmx.de wrote:
>>>>
>>>> Dale <rdalek1967@gmail.com> [16-10-31 18:36]:
>>>>> Meino.Cramer@gmx.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"

-- 
Alan McKinnon
alan.mckinnon@gmail.com

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@gmx.de wrote:
> >>>>
> >>>> Dale <rdalek1967@gmail.com> [16-10-31 18:36]:
> >>>>> Meino.Cramer@gmx.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@ccs.covici.com