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Groups > comp.arch.embedded > #29019
| From | Niklas Holsti <niklas.holsti@tidorum.invalid> |
|---|---|
| Newsgroups | comp.arch.embedded |
| Subject | Re: Task priorities in non strictly real-time systems |
| Date | 2020-01-05 22:44 +0200 |
| Organization | Tidorum Ltd |
| Message-ID | <h7f05rFcs2mU1@mid.individual.net> (permalink) |
| References | <qung9m$m79$1@dont-email.me> <h791buF5513U1@mid.individual.net> <qurb4f$l2c$1@dont-email.me> <qute0f$vk4$2@dont-email.me> |
On 2020-01-05 21:46, Les Cargill wrote:
> pozz wrote:
>>
>> Yes, converting a blocking task in a non-blocking state-machine task
>> can be hard, but it's complex to write tasks in a preemption schuduler
>> (you need to know when to use locks, semaphores, mutexes and so on).
I think that makes it sound harder than it is. Avoid directly shared
variables when you can, using whatever message-passing tools the
language or RTOS provides, or wrap all operations that access shared
data in mutexes, and that will solve most problems.
What remains is mainly the skill and experience to design the shared
data structures so that the mutex-protected operations are short and
snappy without introducing polling, race conditions, deadlocks or
starvation. But that polish is needed only for systems where processing
resources are tight, which is not often the case today.
> The question becomes - how important is determinism in your system? IMO,
> this can be expressed in economic terms - more determinism means fewer
> times the phone rings.
I've been implementing pre-emptive, priority-driven real-time systems,
off and on, since the mid-80's and never has the phone rung because of
the non-determinism.
Yes, many customer write requirements saying that they want "simple,
deterministic scheduling", and then write other requirements for which
the only clean solution is a pre-emptive system.
--
Niklas Holsti
Tidorum Ltd
niklas holsti tidorum fi
. @ .
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Task priorities in non strictly real-time systems pozz <pozzugno@gmail.com> - 2020-01-03 14:41 +0100
Re: Task priorities in non strictly real-time systems David Brown <david.brown@hesbynett.no> - 2020-01-03 15:19 +0100
Re: Task priorities in non strictly real-time systems pozz <pozzugno@gmail.com> - 2020-01-05 01:25 +0100
Re: Task priorities in non strictly real-time systems Les Cargill <lcargill99@comcast.com> - 2020-01-05 13:32 -0600
Re: Task priorities in non strictly real-time systems Richard Damon <Richard@Damon-Family.org> - 2020-01-05 16:49 -0500
Re: Task priorities in non strictly real-time systems Les Cargill <lcargill99@comcast.com> - 2020-01-05 21:05 -0600
Re: Task priorities in non strictly real-time systems Don Y <blockedofcourse@foo.invalid> - 2020-01-05 17:08 -0700
Re: Task priorities in non strictly real-time systems Les Cargill <lcargill99@comcast.com> - 2020-01-05 21:26 -0600
Re: Task priorities in non strictly real-time systems Don Y <blockedofcourse@foo.invalid> - 2020-01-05 22:10 -0700
Re: Task priorities in non strictly real-time systems Les Cargill <lcargill99@comcast.com> - 2020-01-06 07:37 -0600
Re: Task priorities in non strictly real-time systems Don Y <blockedofcourse@foo.invalid> - 2020-01-06 17:21 -0700
Re: Task priorities in non strictly real-time systems Les Cargill <lcargill99@comcast.com> - 2020-01-07 19:23 -0600
Re: Task priorities in non strictly real-time systems Richard Damon <Richard@Damon-Family.org> - 2020-01-06 20:36 -0500
Re: Task priorities in non strictly real-time systems Les Cargill <lcargill99@comcast.com> - 2020-01-07 01:38 -0600
Re: Task priorities in non strictly real-time systems Richard Damon <Richard@Damon-Family.org> - 2020-01-07 06:53 -0500
Re: Task priorities in non strictly real-time systems George Neuner <gneuner2@comcast.net> - 2020-01-06 07:13 -0500
Re: Task priorities in non strictly real-time systems David Brown <david.brown@hesbynett.no> - 2020-01-07 10:11 +0100
Re: Task priorities in non strictly real-time systems Richard Damon <Richard@Damon-Family.org> - 2020-01-07 07:05 -0500
Re: Task priorities in non strictly real-time systems Les Cargill <lcargill99@comcast.com> - 2020-01-07 19:34 -0600
Re: Task priorities in non strictly real-time systems upsidedown@downunder.com - 2020-01-06 10:44 +0200
Re: Task priorities in non strictly real-time systems Don Y <blockedofcourse@foo.invalid> - 2020-01-06 02:51 -0700
Re: Task priorities in non strictly real-time systems upsidedown@downunder.com - 2020-01-06 15:39 +0200
Re: Task priorities in non strictly real-time systems George Neuner <gneuner2@comcast.net> - 2020-01-06 13:29 -0500
Re: Task priorities in non strictly real-time systems Don Y <blockedofcourse@foo.invalid> - 2020-01-06 14:38 -0700
Re: Task priorities in non strictly real-time systems upsidedown@downunder.com - 2020-01-07 07:05 +0200
Re: Task priorities in non strictly real-time systems George Neuner <gneuner2@comcast.net> - 2020-01-07 13:09 -0500
Re: Task priorities in non strictly real-time systems Dimiter_Popoff <dp@tgi-sci.com> - 2020-01-07 20:53 +0200
Re: Task priorities in non strictly real-time systems Clifford Heath <no.spam@please.net> - 2020-01-08 08:43 +1100
Re: Task priorities in non strictly real-time systems upsidedown@downunder.com - 2020-01-08 00:33 +0200
Re: Task priorities in non strictly real-time systems Dimiter_Popoff <dp@tgi-sci.com> - 2020-01-08 15:26 +0200
Re: Task priorities in non strictly real-time systems upsidedown@downunder.com - 2020-01-08 00:08 +0200
Re: Task priorities in non strictly real-time systems David Brown <david.brown@hesbynett.no> - 2020-01-07 10:37 +0100
Re: Task priorities in non strictly real-time systems Don Y <blockedofcourse@foo.invalid> - 2020-01-06 16:10 -0700
Re: Task priorities in non strictly real-time systems upsidedown@downunder.com - 2020-01-07 07:37 +0200
Re: Task priorities in non strictly real-time systems Les Cargill <lcargill99@comcast.com> - 2020-01-07 01:49 -0600
Re: Task priorities in non strictly real-time systems Don Y <blockedofcourse@foo.invalid> - 2020-01-07 06:43 -0700
Re: Task priorities in non strictly real-time systems upsidedown@downunder.com - 2020-01-07 10:21 +0200
Re: Task priorities in non strictly real-time systems Don Y <blockedofcourse@foo.invalid> - 2020-01-07 06:42 -0700
Re: Task priorities in non strictly real-time systems Richard Damon <Richard@Damon-Family.org> - 2020-01-07 22:23 -0500
Re: Task priorities in non strictly real-time systems upsidedown@downunder.com - 2020-01-09 22:07 +0200
Re: Task priorities in non strictly real-time systems upsidedown@downunder.com - 2020-01-07 10:54 +0200
Re: Task priorities in non strictly real-time systems Don Y <blockedofcourse@foo.invalid> - 2020-01-07 06:43 -0700
Re: Task priorities in non strictly real-time systems Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2020-01-06 18:01 +0100
Re: Task priorities in non strictly real-time systems Niklas Holsti <niklas.holsti@tidorum.invalid> - 2020-01-06 19:47 +0200
Re: Task priorities in non strictly real-time systems pozz <pozzugno@gmail.com> - 2020-01-05 01:58 +0100
Re: Task priorities in non strictly real-time systems Clifford Heath <no.spam@please.net> - 2020-01-05 14:26 +1100
Re: Task priorities in non strictly real-time systems upsidedown@downunder.com - 2020-01-05 11:21 +0200
Re: Task priorities in non strictly real-time systems David Brown <david.brown@hesbynett.no> - 2020-01-05 14:07 +0100
Re: Task priorities in non strictly real-time systems upsidedown@downunder.com - 2020-01-05 17:46 +0200
Re: Task priorities in non strictly real-time systems David Brown <david.brown@hesbynett.no> - 2020-01-05 19:08 +0100
Re: Task priorities in non strictly real-time systems David Brown <david.brown@hesbynett.no> - 2020-01-05 13:56 +0100
Re: Task priorities in non strictly real-time systems Les Cargill <lcargill99@comcast.com> - 2020-01-05 13:39 -0600
Re: Task priorities in non strictly real-time systems Clifford Heath <no.spam@please.net> - 2020-01-06 07:44 +1100
Re: Task priorities in non strictly real-time systems Les Cargill <lcargill99@comcast.com> - 2020-01-05 21:00 -0600
Re: Task priorities in non strictly real-time systems Clifford Heath <no.spam@please.net> - 2020-01-06 14:50 +1100
Re: Task priorities in non strictly real-time systems Les Cargill <lcargill99@comcast.com> - 2020-01-06 07:12 -0600
Re: Task priorities in non strictly real-time systems Paul Rubin <no.email@nospam.invalid> - 2020-01-04 22:34 -0800
Re: Task priorities in non strictly real-time systems David Brown <david.brown@hesbynett.no> - 2020-01-05 14:12 +0100
Re: Task priorities in non strictly real-time systems Niklas Holsti <niklas.holsti@tidorum.invalid> - 2020-01-05 18:00 +0200
Re: Task priorities in non strictly real-time systems Les Cargill <lcargill99@comcast.com> - 2020-01-05 13:44 -0600
Re: Task priorities in non strictly real-time systems George Neuner <gneuner2@comcast.net> - 2020-01-06 14:52 -0500
Re: Task priorities in non strictly real-time systems George Neuner <gneuner2@comcast.net> - 2020-01-06 15:05 -0500
Re: Task priorities in non strictly real-time systems gtwrek@sonic.net (gtwrek) - 2020-01-06 22:41 +0000
Re: Task priorities in non strictly real-time systems Don Y <blockedofcourse@foo.invalid> - 2020-01-06 19:50 -0700
Re: Task priorities in non strictly real-time systems George Neuner <gneuner2@comcast.net> - 2020-01-07 13:26 -0500
Re: Task priorities in non strictly real-time systems Niklas Holsti <niklas.holsti@tidorum.invalid> - 2020-01-03 16:28 +0200
Re: Task priorities in non strictly real-time systems pozz <pozzugno@gmail.com> - 2020-01-05 01:37 +0100
Re: Task priorities in non strictly real-time systems Les Cargill <lcargill99@comcast.com> - 2020-01-05 13:46 -0600
Re: Task priorities in non strictly real-time systems Niklas Holsti <niklas.holsti@tidorum.invalid> - 2020-01-05 22:44 +0200
Re: Task priorities in non strictly real-time systems Rick C <gnuarm.deletethisbit@gmail.com> - 2020-01-03 11:49 -0800
Re: Task priorities in non strictly real-time systems upsidedown@downunder.com - 2020-01-03 22:51 +0200
Re: Task priorities in non strictly real-time systems pozz <pozzugno@gmail.com> - 2020-01-05 01:48 +0100
Re: Task priorities in non strictly real-time systems Joe Chisolm <jchisolm6@earthlink.net> - 2020-01-03 15:34 -0600
Re: Task priorities in non strictly real-time systems Richard Damon <Richard@Damon-Family.org> - 2020-01-03 21:46 -0500
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