[cip-dev] [OBSOLETE?] CONFIG_PREEMPT_RT_FULL config parameter in 4.19?!

[cip-dev] [OBSOLETE?] CONFIG_PREEMPT_RT_FULL config parameter in 4.19?!

[Zoran S]

Hello  Ben, Daniel,

I started my own investigation about RT kernels, namely 4.19. I
proceed very carefully over the kernel config parameters... BUt the
last one I inspected today got me nowhere!?

Seems, that the following config parameters are obsolete in 4.19:
CONFIG_PREEMPT_RT_FULL

This one (CONFIG_PREEMPT_RT_FULL) is still present in 4.4 .

[vuser at fedora30-ssd kernel-config]$ cat CONFIG-4.4.120-rt-bbb | grep PREEMPT
CONFIG_PREEMPT_RCU=y
CONFIG_PREEMPT=y
CONFIG_PREEMPT_RT_BASE=y
CONFIG_HAVE_PREEMPT_LAZY=y
CONFIG_PREEMPT_LAZY=y
# CONFIG_PREEMPT_NONE is not set
# CONFIG_PREEMPT_VOLUNTARY is not set
# CONFIG_PREEMPT__LL is not set
# CONFIG_PREEMPT_RTB is not set
CONFIG_PREEMPT_RT_FULL=y <<======= Obsolete in 4.19 ?
CONFIG_PREEMPT_COUNT=y
CONFIG_DEBUG_PREEMPT=y
[vuser@fedora30-ssd kernel-config]$

What I should do to maintain RT-kernel-4.19? It is obvious, I must/need to set:
CONFIG_PREEMPT=y

Anything else?

Any viable/reasonable explanation why CONFIG_PREEMPT_RT_FULL was
removed in 4.19?

Thank you,
Zoran Stojsavljevic
_______

[cip-dev] [OBSOLETE?] CONFIG_PREEMPT_RT_FULL config parameter in 4.19?!

[Ben Hutchings]

On Fri, 2019-07-19 at 15:31 +0200, Zoran S wrote:
> Hello  Ben, Daniel,
> 
> I started my own investigation about RT kernels, namely 4.19. I
> proceed very carefully over the kernel config parameters... BUt the
> last one I inspected today got me nowhere!?
> 
> Seems, that the following config parameters are obsolete in 4.19:
> CONFIG_PREEMPT_RT_FULL
[...]

This never existed in the upstream kernel, only in -rt branches.  It
still exists in 4.19-rt.

Ben.

-- 
Ben Hutchings, Software Developer                         Codethink Ltd
https://www.codethink.co.uk/                 Dale House, 35 Dale Street
                                     Manchester, M1 2HF, United Kingdom

[cip-dev] [OBSOLETE?] CONFIG_PREEMPT_RT_FULL config parameter in 4.19?!

[Zoran S]

> This never existed in the upstream kernel, only in -rt branches.
> It still exists in 4.19-rt.

Sure. The following is done by me:

git clone git://git.kernel.org/pub/scm/linux/kernel/git/cip/linux-cip.git

*Isn't this CIP RT-kernel real-time tree?*

cd linux-cip
*git checkout -b cip_v4.19.58-cip6 v4.19.58-cip6*

make -j4 -k -s ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- O=build-arm
*omap2plus_defconfig*

Please, check the folllowing:

Linux stretch 4.19.0-5-amd64 #1 SMP Debian 4.19.37-5 (2019-06-19) x86_64

vagrant at stretch:~/git-repos/linux-cip/build-arm$ pwd
/home/vagrant/git-repos/linux-cip/build-arm
vagrant at stretch:~/git-repos/linux-cip/build-arm$ ls -al .config
*-rw-r--r-- 1 vagrant vagrant 148183 Jul 18 04:25 .config*
vagrant at stretch:~/git-repos/linux-cip/build-arm$ cat .config | grep PREEMPT
CONFIG_PREEMPT_NONE=y
# CONFIG_PREEMPT_VOLUNTARY is not set
# CONFIG_PREEMPT is not set
CONFIG_PREEMPTIRQ_TRACEPOINTS=y
# CONFIG_PREEMPTIRQ_EVENTS is not set
# CONFIG_PREEMPTIRQ_DELAY_TEST is not set
vagrant at stretch:~/git-repos/linux-cip/build-arm $

And, finally:

vagrant at stretch:~/git-repos/linux-cip$ pwd
/home/vagrant/git-repos/linux-cip
vagrant at stretch:~/git-repos/linux-cip$ ack CONFIG_PREEMPT_RT_FULL
vagrant at stretch:~/git-repos/linux-cip$

Hmmmmmm... Strange, isn't it??? Please, advise?

Thank you,
Zoran Stojsavljevic
_______


On Fri, Jul 19, 2019 at 3:58 PM Ben Hutchings <ben.hutchings@codethink.co.uk>
wrote:

> On Fri, 2019-07-19 at 15:31 +0200, Zoran S wrote:
> > Hello  Ben, Daniel,
> >
> > I started my own investigation about RT kernels, namely 4.19. I
> > proceed very carefully over the kernel config parameters... BUt the
> > last one I inspected today got me nowhere!?
> >
> > Seems, that the following config parameters are obsolete in 4.19:
> > CONFIG_PREEMPT_RT_FULL
> [...]
>
> This never existed in the upstream kernel, only in -rt branches.  It
> still exists in 4.19-rt.
>
> Ben.
>
> --
> Ben Hutchings, Software Developer                         Codethink Ltd
> https://www.codethink.co.uk/                 Dale House, 35 Dale Street
>                                      Manchester, M1 2HF, United Kingdom
>
>
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[cip-dev] [OBSOLETE?] CONFIG_PREEMPT_RT_FULL config parameter in 4.19?!

[Ben Hutchings]

On Fri, 2019-07-19 at 19:58 +0200, Zoran S wrote:
> > This never existed in the upstream kernel, only in -rt branches.
> > It still exists in 4.19-rt.
> 
> Sure. The following is done by me:
> 
> git clone git://git.kernel.org/pub/scm/linux/kernel/git/cip/linux-cip.git
> 
> Isn't this CIP RT-kernel real-time tree?
[...]

It's the CIP kernel repository.  Only the branches with "-rt" in the
name include the real-time patch set.

Ben.

-- 
Ben Hutchings, Software Developer                         Codethink Ltd
https://www.codethink.co.uk/                 Dale House, 35 Dale Street
                                     Manchester, M1 2HF, United Kingdom

[cip-dev] [OBSOLETE?] CONFIG_PREEMPT_RT_FULL config parameter in 4.19?!

[Zoran S]

OK, I see. Wrong check-out!

*git checkout -b cip_v4.19.58-cip6 v4.19.58-cip6*

Yup... This is the root cause of the problem!

v4.19.13-cip1

*v4.19.13-cip1-rt1v4.19.13-cip1-rt1-rebase*
v4.19.13-cip2
v4.19.13-cip2-rebase
v4.19.50-cip3
v4.19.50-cip3-rebase
v4.19.52-cip4
v4.19.52-cip4-rebase
v4.19.56-cip5
v4.19.56-cip5-rebase
v4.19.58-cip6
v4.19.58-cip6-rebase

Psychological mislead! Well... Blind trust in what I see (and I do see NOT
reality, just what I did expect! ;-)

Well, I need to fix this psychosocial problems with my brain! :-)

Case Closed!

Thank you,
Zoran
_______


On Fri, Jul 19, 2019 at 8:11 PM Ben Hutchings <ben.hutchings@codethink.co.uk>
wrote:

> On Fri, 2019-07-19 at 19:58 +0200, Zoran S wrote:
> > > This never existed in the upstream kernel, only in -rt branches.
> > > It still exists in 4.19-rt.
> >
> > Sure. The following is done by me:
> >
> > git clone git://
> git.kernel.org/pub/scm/linux/kernel/git/cip/linux-cip.git
> >
> > Isn't this CIP RT-kernel real-time tree?
> [...]
>
> It's the CIP kernel repository.  Only the branches with "-rt" in the
> name include the real-time patch set.
>
> Ben.
>
> --
> Ben Hutchings, Software Developer                         Codethink Ltd
> https://www.codethink.co.uk/                 Dale House, 35 Dale Street
>                                      Manchester, M1 2HF, United Kingdom
>
>
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[cip-dev] [OBSOLETE?] CONFIG_PREEMPT_RT_FULL config parameter in 4.19?!

[Daniel Wagner]

On 7/19/19 9:03 PM, Zoran S wrote:
> v4.19.58-cip6
> v4.19.58-cip6-rebase

There is also a corresponding branch for those tags.

  - linux-4.4.y-cip-rt:
      contains the -rt patchses. no rebases, just merges.
  - linux-4.4.y-cip-rt-rebase:
      has the -rt patches on top of the last cip release.

[cip-dev] [OBSOLETE?] CONFIG_PREEMPT_RT_FULL config parameter in 4.19?!

[Pavel Machek]

Hi!

> I started my own investigation about RT kernels, namely 4.19. I
> proceed very carefully over the kernel config parameters... BUt the
> last one I inspected today got me nowhere!?
> 
> Seems, that the following config parameters are obsolete in 4.19:
> CONFIG_PREEMPT_RT_FULL
> 
> This one (CONFIG_PREEMPT_RT_FULL) is still present in 4.4 .
> 
> [vuser at fedora30-ssd kernel-config]$ cat CONFIG-4.4.120-rt-bbb | grep PREEMPT
> CONFIG_PREEMPT_RCU=y
> CONFIG_PREEMPT=y
> CONFIG_PREEMPT_RT_BASE=y
> CONFIG_HAVE_PREEMPT_LAZY=y
> CONFIG_PREEMPT_LAZY=y
> # CONFIG_PREEMPT_NONE is not set
> # CONFIG_PREEMPT_VOLUNTARY is not set
> # CONFIG_PREEMPT__LL is not set
> # CONFIG_PREEMPT_RTB is not set
> CONFIG_PREEMPT_RT_FULL=y <<======= Obsolete in 4.19 ?
> CONFIG_PREEMPT_COUNT=y
> CONFIG_DEBUG_PREEMPT=y
> [vuser at fedora30-ssd kernel-config]$
> 
> What I should do to maintain RT-kernel-4.19? It is obvious, I must/need to set:
> CONFIG_PREEMPT=y

Are you sure you have your kernel patched with -rt patches?
CONFIG_PREEMPT_RT_FULL=y was still needed in 4.19, AFAICT.

Note that not every piece of hardware has suitable characteristics for
realtime / low latencies.

Best regards,
									Pavel

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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[cip-dev] [OBSOLETE?] CONFIG_PREEMPT_RT_FULL config parameter in 4.19?!

[Zoran S]

> Are you sure you have your kernel patched with -rt patches?
> CONFIG_PREEMPT_RT_FULL=y was still needed in 4.19, AFAICT.

Please, could you refer to reply above (practical exercises using
lava_server_vm VM) to Ben and Daniel? You can also check and verify
it...

Maybe, after all, I am doing something very wrong. But I do not
see/not aware what?!

Zoran
_______


On Fri, Jul 19, 2019 at 3:59 PM Pavel Machek <pavel@ucw.cz> wrote:
>
> Hi!
>
> > I started my own investigation about RT kernels, namely 4.19. I
> > proceed very carefully over the kernel config parameters... BUt the
> > last one I inspected today got me nowhere!?
> >
> > Seems, that the following config parameters are obsolete in 4.19:
> > CONFIG_PREEMPT_RT_FULL
> >
> > This one (CONFIG_PREEMPT_RT_FULL) is still present in 4.4 .
> >
> > [vuser at fedora30-ssd kernel-config]$ cat CONFIG-4.4.120-rt-bbb | grep PREEMPT
> > CONFIG_PREEMPT_RCU=y
> > CONFIG_PREEMPT=y
> > CONFIG_PREEMPT_RT_BASE=y
> > CONFIG_HAVE_PREEMPT_LAZY=y
> > CONFIG_PREEMPT_LAZY=y
> > # CONFIG_PREEMPT_NONE is not set
> > # CONFIG_PREEMPT_VOLUNTARY is not set
> > # CONFIG_PREEMPT__LL is not set
> > # CONFIG_PREEMPT_RTB is not set
> > CONFIG_PREEMPT_RT_FULL=y <<======= Obsolete in 4.19 ?
> > CONFIG_PREEMPT_COUNT=y
> > CONFIG_DEBUG_PREEMPT=y
> > [vuser at fedora30-ssd kernel-config]$
> >
> > What I should do to maintain RT-kernel-4.19? It is obvious, I must/need to set:
> > CONFIG_PREEMPT=y
>
> Are you sure you have your kernel patched with -rt patches?
> CONFIG_PREEMPT_RT_FULL=y was still needed in 4.19, AFAICT.
>
> Note that not every piece of hardware has suitable characteristics for
> realtime / low latencies.
>
> Best regards,
>                                                                         Pavel
>
> --
> (english) http://www.livejournal.com/~pavelmachek
> (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html