Ola, Are you concerned with lower system-wide scheduling latency or with predictable response times for a particular task?
I believe SCHED_DEADLINE with help with the later. /Amit On Mon, May 20, 2013 at 1:10 PM, Ola Liljedahl <ola.liljed...@arm.com> wrote: > 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.kuche...@linaro.org] > Sent: 19 May 2013 11:51 > To: Mark Orvek > Cc: Patrick MacCartee; Mike Holmes; linaro-networking; Lists linaro-dev; > j.le...@sssup.it; linaro-enterpr...@linaro.org; lng...@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.or...@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 <pmaccar...@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.hol...@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 > > Amit Kucheria > > 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 > > _______________________________________________ > linaro-dev mailing list > > linar...@lists.linaro.org > http://lists.linaro.org/mailman/listinfo/linaro-dev > > > > -- > David Rusling > CTO > Linaro Ltd > > e. david....@linaro.org > > > w. http://www.linaro.org > Linaro: The future of Linux on ARM > > > > > > -- > Patrick J. MacCartee > Director of Product Management > MontaVista Software LLC > fone: 408-572-7937 > mobile: 415-637-0257 > pmaccar...@mvista.com > > > > > > -- > > Mark Orvek > > > > mark.or...@linaro.org > > > > VP, Engineering > > > > M: +1.408.313.6988 IRC: morvek Skype: morvek > > linaro.org │ Open source software for ARM SoCs > > > > > > > -- IMPORTANT NOTICE: The contents of this email and any attachments are > confidential and may also be privileged. If you are not the intended > recipient, please notify the sender immediately and do not disclose the > contents to any other person, use it for any purpose, or store or copy the > information in any medium. Thank you. _______________________________________________ linaro-dev mailing list linaro-dev@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-dev
