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Re: Interrupts: can be lost?

From pozz <pozzugno@gmail.com>
Newsgroups comp.arch.embedded
Subject Re: Interrupts: can be lost?
Date 2020-07-08 13:19 +0200
Organization A noiseless patient Spider
Message-ID <re4a4r$ith$1@dont-email.me> (permalink)
References <re2thr$ke8$3@dont-email.me> <re3r2n$tme$1@dont-email.me>

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Il 08/07/2020 09:02, David Brown ha scritto:
> On 08/07/2020 00:38, pozz wrote:
>> https://www.safetty.net/download/pont_pttes_2001.pdf
>>
>> Page 13
>> Note carefully what this means! There is a common misconception among
>> the developers of embedded applications that interrupt events will never
>> be lost. This simply is not true. If you have multiple sources of
>> interrupts that may appear at ‘random’ time intervals, interrupt
>> responses can be missed: indeed, where there are several active
>> interrupt sources, it is practically impossible to create code that will
>> deal correctly with all possible combinations of interrupts.
>>
>> Those words are incredible for me. I suspect I didn't get the point of
>> the author. I don't think that interrupt events on modern microntrollers
>> can be lost in some circumstances.
> 
> The book was written in 2001, using a microcontroller that, while very
> popular (and still not dead), was 20 years out of date at the time.  I
> haven't looked at it yet, and can't judge the quality of the book.  But
> beware that some things in it could be limited by that microcontroller
> architecture.
> 
> However, the principle here is correct.  It is part of a more general
> principle that is actually quite simple:
> 
> If you have event counters or trackers that have limited capacity, and
> you do not handle the events before that capacity is exceeded, your
> system will lose events (by either ignoring new ones, or ejecting old ones).

However I have the suspect the author didn't refer to multiple events of 
the *same* source.

 > [...] If you have multiple sources of interrupts [...] it is
 > practically impossible to create code that will deal correctly
 > with all possible combinations of interrupts.

It's yet an obscure sentence for me. A sentence that seems to be the 
foundation of the entire book.

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Thread

Interrupts: can be lost? pozz <pozzugno@gmail.com> - 2020-07-08 00:38 +0200
  Re: Interrupts: can be lost? Clifford Heath <no.spam@please.net> - 2020-07-08 09:11 +1000
    Re: Interrupts: can be lost? pozz <pozzugno@gmail.com> - 2020-07-08 08:13 +0200
      Re: Interrupts: can be lost? David Brown <david.brown@hesbynett.no> - 2020-07-08 09:13 +0200
  Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-07 16:14 -0700
    Re: Interrupts: can be lost? pozz <pozzugno@gmail.com> - 2020-07-08 08:16 +0200
      Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-08 06:55 -0700
  Re: Interrupts: can be lost? David Brown <david.brown@hesbynett.no> - 2020-07-08 09:02 +0200
    Re: Interrupts: can be lost? Niklas Holsti <niklas.holsti@tidorum.invalid> - 2020-07-08 11:43 +0300
      Re: Interrupts: can be lost? pozz <pozzugno@gmail.com> - 2020-07-08 12:24 +0200
        Re: Interrupts: can be lost? antispam@math.uni.wroc.pl - 2020-07-09 23:24 +0000
          Re: Interrupts: can be lost? Dave Nadler <drn@nadler.com> - 2020-07-09 17:13 -0700
          Re: Interrupts: can be lost? pozz <pozzugno@gmail.com> - 2020-07-10 08:09 +0200
            Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-09 23:39 -0700
            Re: Interrupts: can be lost? David Brown <david.brown@hesbynett.no> - 2020-07-10 08:59 +0200
      Re: Interrupts: can be lost? Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2020-07-08 14:57 +0300
        Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-08 07:01 -0700
          Re: Interrupts: can be lost? David Brown <david.brown@hesbynett.no> - 2020-07-08 16:07 +0200
            Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-08 07:35 -0700
              Re: Interrupts: can be lost? David Brown <david.brown@hesbynett.no> - 2020-07-09 14:16 +0200
                Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-09 11:04 -0700
                Re: Interrupts: can be lost? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2020-07-09 14:32 -0400
                Re: Interrupts: can be lost? Paul Rubin <no.email@nospam.invalid> - 2020-07-09 11:47 -0700
                Re: Interrupts: can be lost? lasselangwadtchristensen@gmail.com - 2020-07-09 15:22 -0700
                Re: Interrupts: can be lost? Dave Nadler <drn@nadler.com> - 2020-07-09 15:35 -0700
                Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-09 18:41 -0700
                Re: Interrupts: can be lost? Clifford Heath <no.spam@please.net> - 2020-07-10 16:01 +1000
                Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-09 23:28 -0700
                Re: Interrupts: can be lost? Chris <xxx.syseng.yyy@gfsys.co.uk> - 2020-07-29 19:44 +0100
                Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-29 13:23 -0700
                Re: Interrupts: can be lost? Chris <xxx.syseng.yyy@gfsys.co.uk> - 2020-07-29 22:57 +0100
                Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-29 16:47 -0700
                Re: Interrupts: can be lost? Clifford Heath <no.spam@please.net> - 2020-07-30 10:04 +1000
                Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-29 17:46 -0700
                Re: Interrupts: can be lost? Clifford Heath <no.spam@please.net> - 2020-07-30 11:04 +1000
                Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-29 21:16 -0700
                Re: Interrupts: can be lost? Clifford Heath <no.spam@please.net> - 2020-07-30 16:36 +1000
                Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-31 11:26 -0700
                Re: Interrupts: can be lost? Chris <xxx.syseng.yyy@gfsys.co.uk> - 2020-07-30 01:11 +0100
                Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-29 17:53 -0700
                Re: Interrupts: can be lost? Chris <xxx.syseng.yyy@gfsys.co.uk> - 2020-07-30 19:05 +0100
                Re: Interrupts: can be lost? Dimiter_Popoff <dp@tgi-sci.com> - 2020-07-31 00:21 +0300
                Re: Interrupts: can be lost? David Brown <david.brown@hesbynett.no> - 2020-08-04 20:40 +0200
                Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-08-04 14:36 -0700
                Re: Interrupts: can be lost? Richard Damon <Richard@Damon-Family.org> - 2020-08-04 22:32 -0400
                Re: Interrupts: can be lost? David Brown <david.brown@hesbynett.no> - 2020-08-05 15:26 +0200
                Re: Interrupts: can be lost? upsidedown@downunder.com - 2020-07-30 08:31 +0300
                Re: Interrupts: can be lost? Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-07-30 07:53 +0100
                Re: Interrupts: can be lost? Richard Damon <Richard@Damon-Family.org> - 2020-07-30 08:10 -0400
                Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-09 18:40 -0700
                Re: Interrupts: can be lost? David Brown <david.brown@hesbynett.no> - 2020-07-10 09:09 +0200
                Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-10 01:41 -0700
                Re: Interrupts: can be lost? David Brown <david.brown@hesbynett.no> - 2020-07-10 13:47 +0200
                Re: Interrupts: can be lost? Dimiter_Popoff <dp@tgi-sci.com> - 2020-07-11 13:41 +0300
          Re: Interrupts: can be lost? Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2020-07-08 17:33 +0300
            Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-08 09:31 -0700
              Re: Interrupts: can be lost? David Brown <david.brown@hesbynett.no> - 2020-07-09 14:30 +0200
              Re: Interrupts: can be lost? Przemek Klosowski <przemek@tux.dot.org> - 2020-07-19 18:38 +0000
                Re: Interrupts: can be lost? Dimiter_Popoff <dp@tgi-sci.com> - 2020-07-19 23:11 +0300
                Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-19 13:43 -0700
    Re: Interrupts: can be lost? pozz <pozzugno@gmail.com> - 2020-07-08 13:19 +0200
  Re: Interrupts: can be lost? Richard Damon <Richard@Damon-Family.org> - 2020-07-09 08:00 -0400
  Re: Interrupts: can be lost? dalai lamah <antonio12358@hotmail.com> - 2020-07-11 12:12 +0200
    Re: Interrupts: can be lost? pozz <pozzugno@gmail.com> - 2020-07-13 08:35 +0200

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