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Groups > comp.arch.embedded > #29100
| From | Niklas Holsti <niklas.holsti@tidorum.invalid> |
|---|---|
| Newsgroups | comp.arch.embedded |
| Subject | Re: From cooperative to preemptive scheduler: a real example |
| Date | 2020-01-15 18:39 +0200 |
| Organization | Tidorum Ltd |
| Message-ID | <h88thqFpjboU1@mid.individual.net> (permalink) |
| References | (2 earlier) <qv1hve$1oj$1@dont-email.me> <qv25u5$q6h$1@dont-email.me> <qv320p$f1e$1@dont-email.me> <h7n7h8F4d24U1@mid.individual.net> <qv8dpc$k53$1@dont-email.me> |
On 2020-01-10 1:42, pozz wrote:
> Il 09/01/2020 00:39, Niklas Holsti ha scritto:
>> On 2020-01-08 0:51, pozz wrote:
>>> Il 07/01/2020 15:51, Don Y ha scritto:
>>>> On 1/7/2020 2:11 AM, pozz wrote:
>>>>> Il 07/01/2020 03:37, Don Y ha scritto:
>>>>>> On 1/6/2020 6:08 PM, pozz wrote:
>
>> What is your concern with that? You only need one semaphore to provide
>> mutual exclusion between two tasks, not a separate semaphore for each
>> shared variable.
>>
>> Are you worried about the processor time for the semaphore operations?
>> or the code clutter?
>
> Code clutter. I am worried to forget to add semaphore management to a
> newly added function without noticing the problem (because those bugs
> are very rare to see).
You can hide the variables (make them "static" in their own .c file) so
that they can only be accessed through the mutexed functions. Then you
can't forget.
(Ada has a nice feature called the "protected object" that can do that
without needing any explicit semaphore or mutex calls.)
>> You might try coding an FFT or Quicksort or other complex algorithm as
>> a state machine, with a variable overall length of the input and
>> output arrays, and then compare the "clutter" of those state machines
>> with the clutter of pre-emptive coding.
>
> Those are right examples, but I think very rare in typical control systems.
Depends on your definition of "typical". I recently completed a project
which required both FFT and median-of-vector, using a median algorithm
very similar to quick-sort. (To Be Honest: the target had an FFT HW
unit, so that part did not have to be implemented in SW.)
--
Niklas Holsti
Tidorum Ltd
niklas holsti tidorum fi
. @ .
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From cooperative to preemptive scheduler: a real example pozz <pozzugno@gmail.com> - 2020-01-07 02:08 +0100
Re: From cooperative to preemptive scheduler: a real example Don Y <blockedofcourse@foo.invalid> - 2020-01-06 19:37 -0700
Re: From cooperative to preemptive scheduler: a real example pozz <pozzugno@gmail.com> - 2020-01-07 10:11 +0100
Re: From cooperative to preemptive scheduler: a real example Don Y <blockedofcourse@foo.invalid> - 2020-01-07 07:51 -0700
Re: From cooperative to preemptive scheduler: a real example pozz <pozzugno@gmail.com> - 2020-01-07 23:51 +0100
Re: From cooperative to preemptive scheduler: a real example Niklas Holsti <niklas.holsti@tidorum.invalid> - 2020-01-09 01:39 +0200
Re: From cooperative to preemptive scheduler: a real example pozz <pozzugno@gmail.com> - 2020-01-10 00:42 +0100
Re: From cooperative to preemptive scheduler: a real example Niklas Holsti <niklas.holsti@tidorum.invalid> - 2020-01-15 18:39 +0200
Re: From cooperative to preemptive scheduler: a real example Don Y <blockedofcourse@foo.invalid> - 2020-01-08 23:12 -0700
Re: From cooperative to preemptive scheduler: a real example pozz <pozzugno@gmail.com> - 2020-01-10 00:49 +0100
Re: From cooperative to preemptive scheduler: a real example Don Y <blockedofcourse@foo.invalid> - 2020-01-08 23:12 -0700
Re: From cooperative to preemptive scheduler: a real example Don Y <blockedofcourse@foo.invalid> - 2020-01-09 01:33 -0700
Re: From cooperative to preemptive scheduler: a real example Niklas Holsti <niklas.holsti@tidorum.invalid> - 2020-01-07 09:38 +0200
Re: From cooperative to preemptive scheduler: a real example pozz <pozzugno@gmail.com> - 2020-01-08 00:02 +0100
Re: From cooperative to preemptive scheduler: a real example Niklas Holsti <niklas.holsti@tidorum.invalid> - 2020-01-09 00:54 +0200
Re: From cooperative to preemptive scheduler: a real example pozz <pozzugno@gmail.com> - 2020-01-09 12:19 +0100
Re: From cooperative to preemptive scheduler: a real example Niklas Holsti <niklas.holsti@tidorum.invalid> - 2020-01-09 14:03 +0200
Re: From cooperative to preemptive scheduler: a real example pozz <pozzugno@gmail.com> - 2020-01-10 00:32 +0100
Re: From cooperative to preemptive scheduler: a real example Niklas Holsti <niklas.holsti@tidorum.invalid> - 2020-01-15 18:53 +0200
Re: From cooperative to preemptive scheduler: a real example pozz <pozzugno@gmail.com> - 2020-01-16 14:48 +0100
Re: From cooperative to preemptive scheduler: a real example upsidedown@downunder.com - 2020-01-16 21:04 +0200
Re: From cooperative to preemptive scheduler: a real example Niklas Holsti <niklas.holsti@tidorum.invalid> - 2020-01-16 22:24 +0200
Re: From cooperative to preemptive scheduler: a real example pozz <pozzugno@gmail.com> - 2020-01-17 02:05 +0100
Re: From cooperative to preemptive scheduler: a real example Niklas Holsti <niklas.holsti@tidorum.invalid> - 2020-01-18 23:03 +0200
Re: From cooperative to preemptive scheduler [Stack] pozz <pozzugno@gmail.com> - 2020-01-14 13:27 +0100
Re: From cooperative to preemptive scheduler [Stack] Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2020-01-14 20:10 +0100
Re: From cooperative to preemptive scheduler [Stack] pozz <pozzugno@gmail.com> - 2020-01-15 09:36 +0100
Re: From cooperative to preemptive scheduler [Stack] Stef <stef33d@yahooI-N-V-A-L-I-D.com.invalid> - 2020-01-15 11:30 +0100
Re: From cooperative to preemptive scheduler [Stack] pozz <pozzugno@gmail.com> - 2020-01-15 11:51 +0100
Re: From cooperative to preemptive scheduler [Stack] Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2020-01-15 21:51 +0100
Re: From cooperative to preemptive scheduler [Stack] Niklas Holsti <niklas.holsti@tidorum.invalid> - 2020-01-15 21:26 +0200
Re: From cooperative to preemptive scheduler [Stack] Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2020-01-15 22:12 +0100
Re: From cooperative to preemptive scheduler [Stack] Niklas Holsti <niklas.holsti@tidorum.invalid> - 2020-01-15 23:30 +0200
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