Similarly, the SCHED_DEADLINE patches shouldn't affect default runtime scheduler behaviour unless a task uses the DEADLINE policy. 

However, I haven't studied the intersection of the Preempt RT and SCHED_DEADLINE patches in source form yet. If they touch common pieces of code, merging both in might be an ongoing effort. Juri, do you know?


On Fri, May 17, 2013 at 8:11 PM, Mark Orvek <mark.orvek@linaro.org> wrote:
The PREEMPT_RT patchset is configurable.  I believe the default is PREEMPT_DESKTOP which is what most MV CGE customers use.  Another config options is PREEMPT_NONE but I believe its usage is rare.

Mark


On Fri, May 17, 2013 at 7:25 AM, Patrick MacCartee <pmaccartee@mvista.com> wrote:
Will these be added in a way that makes them easy to remove? Many, >95% don't use Preempt RT in Linux as it impacts network performance and makes things very temperamental.  You would think people would just disable this RT, but when trying to isolate issues it adds another variable to the mix. I believe Yocto has a way of adding and removing RT patches that is some what straight forward and preferable based on feedback from OEM's. 

Just a thought, 
Patrick


On Fri, May 17, 2013 at 6:34 AM, Mike Holmes <mike.holmes@linaro.org> wrote:
In LNG you could end up with an interesting mix of preempt RT and deadline patches making the analysis and benchmarking interesting to interpret.
In addition there are discussions about adding zero overhead linux (ZOL) like features.

Mike



On Friday, May 17, 2013 6:08:20 AM UTC-4, David Rusling wrote:
Amit,
    an interesting proposal.  I think that most of the LNG steering committee is on this alias, but just in case, I'm adding them to it...
Dave

17 May 2013 10:15
Hi all,

As part of our investigations into the Linux scheduler we've
interacted with Juri Lelli at the University of Pisa (cc'ed) who is
part of a group that is working on a DEADLINE scheduler[1] for
Linux[2].

While we're coming at this from a power managment angle[3], I suspect
that LEG and LNG already have real-world usecases that would benefit
from deadline scheduler found in other RTOSes.

So I think it makes sense to merge Juri's tree into linux-linaro going
forward to allow easier experimentation. Does LEG and LNG have any
interest in this at this point?

Juri has expressed an interest in maintaining a current branch of the
code that could be merged into our monthly release. In return, real
world usecases will improve his chances of getting the code merged
into mainline.

Regards,
Amit

[1] http://retis.sssup.it/?q=node/35
[2] https://lkml.org/lkml/2013/2/11/373
[3] Mostly involving discussions at this point, no real engineering
effort invested yet

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