In my experience, networking is moving away from realtime scheduling (and thus RTOS’es). There are some lingering requirements for some of the processing in
the wireless stack but the main difficulty here is getting the scheduling latency down to acceptable levels, e.g. five microseconds or so. Will SCHED_DEADLINE help here?
-- Ola
Ola Liljedahl, Networking System Architect, ARM
Telephone: +46 706 866 373 Skype: ola.liljedahl
From: Amit Kucheria [mailto:amit.kucheria@linaro.org]
Sent: 19 May 2013 11:51
To: Mark Orvek
Cc: Patrick MacCartee; Mike Holmes; linaro-networking; Lists linaro-dev; j.lelli@sssup.it; linaro-enterprise@linaro.org; lng-sc@linaro.org
Subject: Re: Deadline scheduler inclusion in linux-linaro?
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: