2.6.35 RT support roadmap

2.6.35 RT support roadmap

[Walzer, Frank]

Hi Folks,

What is the plan for kernel 2.6.35 support with the RT patch?

I know this is a difficult (and unliked) question but I would like at least to get some idea. My management is pushing me for dates when we could run some trials.
If nobody is looking at that we have to come up with some other plan.

Thanks a lot.

Frank


Texas Instruments Deutschland GmbH, Haggertystr. 1, D-85356 Freising. Amtsgericht München HRB 40960. Geschäftsführer: Dr. Wolfram Tietscher. Vorsitzender des Aufsichtsrates: Edgar Frank



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Re: 2.6.35 RT support roadmap

[Xianghua Xiao]

On Tue, Aug 10, 2010 at 2:43 AM, Walzer, Frank <f-walzer@ti.com> wrote:
> Hi Folks,
>
> What is the plan for kernel 2.6.35 support with the RT patch?
>
> I know this is a difficult (and unliked) question but I would like at least to get some idea. My management is pushing me for dates when we could run some trials.
> If nobody is looking at that we have to come up with some other plan.
>
> Thanks a lot.
>
> Frank
>
>
> Texas Instruments Deutschland GmbH, Haggertystr. 1, D-85356 Freising. Amtsgericht München HRB 40960. Geschäftsführer: Dr. Wolfram Tietscher. Vorsitzender des Aufsichtsrates: Edgar Frank
>
>
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

Yes it would be great if we can know which kernel release will have rt
patch for it. So far it seems to like a myth.
Thanks,
Xianghua
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Re: 2.6.35 RT support roadmap

[Mike Galbraith]

On Thu, 2010-08-12 at 09:38 -0500, Xianghua Xiao wrote:
> On Tue, Aug 10, 2010 at 2:43 AM, Walzer, Frank <f-walzer@ti.com> wrote:
> > Hi Folks,
> >
> > What is the plan for kernel 2.6.35 support with the RT patch?
> >
> > I know this is a difficult (and unliked) question but I would like at least to get some idea. My management is pushing me for dates when we could run some trials.
> > If nobody is looking at that we have to come up with some other plan.
> >
> > Thanks a lot.
> >
> > Frank
> >
> >
> > Texas Instruments Deutschland GmbH, Haggertystr. 1, D-85356 Freising. Amtsgericht München HRB 40960. Geschäftsführer: Dr. Wolfram Tietscher. Vorsitzender des Aufsichtsrates: Edgar Frank
> >
> >
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> >
> 
> Yes it would be great if we can know which kernel release will have rt
> patch for it. So far it seems to like a myth.

Perhaps people wanting specific events to happen at specific times
should become more proactive.

	-Mike

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Re: 2.6.35 RT support roadmap

[Sven-Thorsten Dietrich]

  On 08/12/2010 11:38 AM, Mike Galbraith wrote:
> On Thu, 2010-08-12 at 09:38 -0500, Xianghua Xiao wrote:
>> On Tue, Aug 10, 2010 at 2:43 AM, Walzer, Frank<f-walzer@ti.com>  wrote:

It should be noted, that TI (Omap) was instrumental in supporting some 
of the early serious work on RT in the 2004 time frame.

However, in an example of a severe corporate road-map fail, possibly 
caused GPL paranoia, combined probably with a nasty case of 
Symbian-leveraged NIH, Nokia didn't pick up what TI was laying down - 
and in 2005 squandered a fantastic opportunity to take an early lead in 
the linux-phone platfrom space, fizzing out with the 7xx and N800 toys.

Google did Android and even Palm woke up (just long enough to watch its 
own demise).

The rest is history.

Except of course putting the RT Kernel in Android.

I am curious what the German TI folks are doing with RT!

Cheers

Sven



>>> Hi Folks,
>>>
>>> What is the plan for kernel 2.6.35 support with the RT patch?
>>>
>>> I know this is a difficult (and unliked) question but I would like at least to get some idea. My management is pushing me for dates when we could run some trials.
>>> If nobody is looking at that we have to come up with some other plan.
>>>
>>> Thanks a lot.
>>>
>>> Frank
>>>
>>>
>>> Texas Instruments Deutschland GmbH, Haggertystr. 1, D-85356 Freising. Amtsgericht München HRB 40960. Geschäftsführer: Dr. Wolfram Tietscher. Vorsitzender des Aufsichtsrates: Edgar Frank
>>>
>>>
>>>
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in
>>> the body of a message to majordomo@vger.kernel.org
>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>>
>> Yes it would be great if we can know which kernel release will have rt
>> patch for it. So far it seems to like a myth.
> Perhaps people wanting specific events to happen at specific times
> should become more proactive.
>
> 	-Mike
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in
> the body of a message to majordomo@vger.kernel.org
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Re: 2.6.35 RT support roadmap

[jordan johnston]

> Google did Android and even Palm woke up (just long enough to watch its own
> demise).
>
> The rest is history.
>
> Except of course putting the RT Kernel in Android.

As i understand it, many Android users are using the BFS patchset, and
have been for a while. BFS pretty much does what "the end result of
using the rt-patches" accomplish, minus rtirq, spin-locks, etc. You
will get the desired
responsiveness that using RT would give you.

Im pretty sure that is why Zen-kernel has a git repository "very
specifically" for android (BFS is the default kernel setting). I'm
sure there are other goodies for android in there too.

www.zen-kernel.org

I don't know much about the Android repo's state (as it's fairly new).
but worth a
look for your "rt-usage" (ie. performance/responsiveness) for android.
 As i do not own an Android, i have not tested it, but i have talked
with people who do..

I'm waiting to see what 2.6.35 holds for RT.... but personally i am
using BFS and 2.6.34 with a lot of performance tuning (a good deal of
time spent analyzing/tuning) and i am yielding better results not
using the upstream rt-patches.
we will see what happens in 2.6.35/36....

just my 2 cents :)

cheers

jordan

Re: 2.6.35 RT support roadmap

[Sven-Thorsten Dietrich]

On Thu, 2010-08-12 at 23:17 -0400, jordan johnston wrote:
> > Google did Android and even Palm woke up (just long enough to watch its own
> > demise).
> >
> > The rest is history.
> >
> > Except of course putting the RT Kernel in Android.
> 
> As i understand it, many Android users are using the BFS patchset, and
> have been for a while. BFS pretty much does what "the end result of
> using the rt-patches" accomplish, minus rtirq, spin-locks, etc. You
> will get the desired
> responsiveness that using RT would give you.
> 

I assume that it might well depend to some extent on whether I am
pumping market data feeds into a processing model using 512 CPUs or
playing a game on my Nexus-1, but I won't disagree agree with you on the
importance of task-appropriate efficient scheduling, appropriate
workload partitioning, and all that jazz.


> Im pretty sure that is why Zen-kernel has a git repository "very
> specifically" for android (BFS is the default kernel setting). I'm
> sure there are other goodies for android in there too.
> 
> www.zen-kernel.org
> 
> I don't know much about the Android repo's state (as it's fairly new).
> but worth a
> look for your "rt-usage" (ie. performance/responsiveness) for android.
>  As i do not own an Android, i have not tested it, but i have talked
> with people who do..
> 
> I'm waiting to see what 2.6.35 holds for RT.... but personally i am
> using BFS and 2.6.34 with a lot of performance tuning (a good deal of
> time spent analyzing/tuning) and i am yielding better results not
> using the upstream rt-patches.
> we will see what happens in 2.6.35/36....
> 

Sounds good. I know there has been some extensive discussion about the
interpretation and applicability of the various scheduler performance
metrics, including special examination of BFS vs. CFS - and I definitely
think that has been hashed out in gore and detail already.

But if you have some pretty plots that characterize performance for your
platform, vs. Preempt-RT, I am always interested in looking at pictures
and numbers about what's happening on the other side of the fence.

Cheers,

Sven


> just my 2 cents :)
> 
> cheers
> 
> jordan

Re: 2.6.35 RT support roadmap

[Mike Galbraith]

On Thu, 2010-08-12 at 23:17 -0400, jordan johnston wrote:
> > Google did Android and even Palm woke up (just long enough to watch its own
> > demise).
> >
> > The rest is history.
> >
> > Except of course putting the RT Kernel in Android.
> 
> As i understand it, many Android users are using the BFS patchset, and
> have been for a while. BFS pretty much does what "the end result of
> using the rt-patches" accomplish, minus rtirq, spin-locks, etc. You
> will get the desired
> responsiveness that using RT would give you.

Heh, RT kernel patch and BFS _scheduler_ patch are not even on the same
planet.  BFS is probably not a bad choice for a single cache machine
doing soft RT.  I tested it pretty heavily a while back, and it was
generally pretty good.

> Im pretty sure that is why Zen-kernel has a git repository "very
> specifically" for android (BFS is the default kernel setting). I'm
> sure there are other goodies for android in there too.
> 
> www.zen-kernel.org
> 
> I don't know much about the Android repo's state (as it's fairly new).
> but worth a
> look for your "rt-usage" (ie. performance/responsiveness) for android.
>  As i do not own an Android, i have not tested it, but i have talked
> with people who do..
> 
> I'm waiting to see what 2.6.35 holds for RT.... but personally i am
> using BFS and 2.6.34 with a lot of performance tuning (a good deal of
> time spent analyzing/tuning) and i am yielding better results not
> using the upstream rt-patches.
> we will see what happens in 2.6.35/36....

It depends on what you're calling performance.  A non-rt kernel
absolutely will outperform the rt kernel in many respects.  For
instance, if your measure of performance is the time it takes to play
one byte ping-pong over localhost (eg netperf TCP_RR), the rt kernel
will (does) lose badly due to context switch cost between various rt
middle-man threads.  If your performance criteria is things like
priority inversion tests, suddenly the comparison does a flipflop.

	-Mike

Re: 2.6.35 RT support roadmap

[jordan johnston]

On Fri, Aug 13, 2010 at 2:05 AM, Sven-Thorsten Dietrich
<thebigcorporation@gmail.com> wrote:
> On Thu, 2010-08-12 at 23:17 -0400, jordan johnston wrote:
>> > Google did Android and even Palm woke up (just long enough to watch its own
>> > demise).
>> >
>> > The rest is history.
>> >
>> > Except of course putting the RT Kernel in Android.
>>
>> As i understand it, many Android users are using the BFS patchset, and
>> have been for a while. BFS pretty much does what "the end result of
>> using the rt-patches" accomplish, minus rtirq, spin-locks, etc. You
>> will get the desired
>> responsiveness that using RT would give you.
>>
>
> I assume that it might well depend to some extent on whether I am
> pumping market data feeds into a processing model using 512 CPUs or
> playing a game on my Nexus-1, but I won't disagree agree with you on the
> importance of task-appropriate efficient scheduling, appropriate
> workload partitioning, and all that jazz.

agreed, 100%. the "case in point" here is i was commenting on android.
When talking on the scale of 512 CPUs,
RT is the choice hands down. i should have said "You will get the
desired responsiveness that using RT would give you ON ANDROID".

>> Im pretty sure that is why Zen-kernel has a git repository "very
>> specifically" for android (BFS is the default kernel setting). I'm
>> sure there are other goodies for android in there too.
>>
>> www.zen-kernel.org
>>
>> I don't know much about the Android repo's state (as it's fairly new).
>> but worth a
>> look for your "rt-usage" (ie. performance/responsiveness) for android.
>>  As i do not own an Android, i have not tested it, but i have talked
>> with people who do..
>>
>> I'm waiting to see what 2.6.35 holds for RT.... but personally i am
>> using BFS and 2.6.34 with a lot of performance tuning (a good deal of
>> time spent analyzing/tuning) and i am yielding better results not
>> using the upstream rt-patches.
>> we will see what happens in 2.6.35/36....
>>
>
> Sounds good. I know there has been some extensive discussion about the
> interpretation and applicability of the various scheduler performance
> metrics, including special examination of BFS vs. CFS - and I definitely
> think that has been hashed out in gore and detail already.
>
> But if you have some pretty plots that characterize performance for your
> platform, vs. Preempt-RT, I am always interested in looking at pictures
> and numbers about what's happening on the other side of the fence.

Of course, i wasn't interested in getting into the CFS/BFS war. they
are both valid and useful.
I also think the existence of both, is a good thing. if anything it's
healthy for development.
I do plan to document some of my testing/usage but not until i get my
new 3u rack up and running.

jordan
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RE: 2.6.35 RT support roadmap

[Walzer, Frank]

Sven,

> It should be noted, that TI (Omap) was instrumental in supporting some
> of the early serious work on RT in the 2004 time frame.
>
Actually something I did not know... At that time I only started to use Linux for embedded devices.

> I am curious what the German TI folks are doing with RT!

That is no secret. We have the Industrial Automation Lab here, which works on support and solutions for the IA market targeting mainly ARM9 (AM1xxx) and Cortex-A8 (AM3xxx) based devices. RT Linux is a fixed requirement in many of the apps.

Enough advertising... shoot me a mail if you like to know more (f-walzer at ti.com).

Regards,
  Frank

Texas Instruments Deutschland GmbH, Haggertystr. 1, D-85356 Freising. Amtsgericht München HRB 40960. Geschäftsführer: Dr. Wolfram Tietscher. Vorsitzender des Aufsichtsrates: Edgar Frank



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Re: 2.6.35 RT support roadmap

[Clark Williams]

[-- Attachment #1: Type: text/plain, Size: 1386 bytes --]

On Thu, 12 Aug 2010 09:38:18 -0500
Xianghua Xiao <xiaoxianghua@gmail.com> wrote:

> On Tue, Aug 10, 2010 at 2:43 AM, Walzer, Frank <f-walzer@ti.com> wrote:
> > Hi Folks,
> >
> > What is the plan for kernel 2.6.35 support with the RT patch?
> >
> > I know this is a difficult (and unliked) question but I would like at least to get some idea. My management is pushing me for dates when we could run some trials.
> > If nobody is looking at that we have to come up with some other plan.
> >
> > Thanks a lot.
> >
> > Frank
> >
> >
> > Texas Instruments Deutschland GmbH, Haggertystr. 1, D-85356 Freising. Amtsgericht München HRB 40960. Geschäftsführer: Dr. Wolfram Tietscher. Vorsitzender des Aufsichtsrates: Edgar Frank
> >
> >
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> >
> 
> Yes it would be great if we can know which kernel release will have rt
> patch for it. So far it seems to like a myth.

When I last talked with Thomas (a bit over a week ago) the plan was to
release an rt patch for the 2.6.35 tree. My guess is that when Thomas
gets back (he's on vacation this week), he will forward port the current
2.6.33.7-rt29 to 2.6.35 and we'll have a new -rt patch.

Clark

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Re: 2.6.35 RT support roadmap

[Sven-Thorsten Dietrich]

On Tue, 2010-08-17 at 12:00 -0500, Clark Williams wrote:
> On Thu, 12 Aug 2010 09:38:18 -0500
> Xianghua Xiao <xiaoxianghua@gmail.com> wrote:
> 
> > On Tue, Aug 10, 2010 at 2:43 AM, Walzer, Frank <f-walzer@ti.com> wrote:
> > > Hi Folks,
> > >
> > > What is the plan for kernel 2.6.35 support with the RT patch?
> > >
> > > I know this is a difficult (and unliked) question but I would like at least to get some idea. My management is pushing me for dates when we could run some trials.
> > > If nobody is looking at that we have to come up with some other plan.
> > >
> > > Thanks a lot.
> > >
> > > Frank
> > >
> > >
> > > Texas Instruments Deutschland GmbH, Haggertystr. 1, D-85356 Freising. Amtsgericht München HRB 40960. Geschäftsführer: Dr. Wolfram Tietscher. Vorsitzender des Aufsichtsrates: Edgar Frank
> > >
> > >
> > >
> > > --
> > > To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in
> > > the body of a message to majordomo@vger.kernel.org
> > > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > >
> > 
> > Yes it would be great if we can know which kernel release will have rt
> > patch for it. So far it seems to like a myth.
> 
> When I last talked with Thomas (a bit over a week ago) the plan was to
> release an rt patch for the 2.6.35 tree. My guess is that when Thomas
> gets back (he's on vacation this week), he will forward port the current
> 2.6.33.7-rt29 to 2.6.35 and we'll have a new -rt patch.
> 

That will be the 25th Kernel version (and almost 6 years) since the
first PREEMPT_RT patch at 2.6.10.

A bit of an anni-vers-ary.

I'll raise a toast to y'all.

Cheers,

Sven


> Clark


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