Re: Embedded platforms for beginners?

From	Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net>
Newsgroups	comp.arch.embedded
Subject	Re: Embedded platforms for beginners?
Date	2017-09-05 16:56 -0400
Organization	A noiseless patient Spider
Message-ID	<oongdp$54c$1@dont-email.me> (permalink)
References	(9 earlier) <QX_qB.47681$NF2.20064@fx27.iad> <ooi22u$riv$2@dont-email.me> <lG0rB.65702$EZ2.14489@fx22.iad> <v4OdnVKvv-PMBjHEnZ2dnUU7-LOdnZ2d@supernews.com> <2i5rB.35182$OC1.2645@fx06.iad>

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On 09/04/2017 01:13 AM, Clifford Heath wrote:
> On 04/09/17 10:16, Phil Hobbs wrote:
>> On 09/03/2017 07:58 PM, Clifford Heath wrote:
>>> On 04/09/17 09:13, Phil Hobbs wrote:
>>>> On 09/03/2017 06:00 PM, Clifford Heath wrote:
>>>>> On 04/09/17 05:58, George Neuner wrote:
>>>>>> On Sun, 3 Sep 2017 17:52:42 +1000, Clifford Heath 
>>>>>> <no.spam@please.net>
>>>>>> wrote:
>>>>>>
>>>>>>> On 03/09/17 16:14, rickman wrote:
>>>>>>>> What is GC?
>>>>>>>
>>>>>>> Garbage collection. Make new objects and just lose them,
>>>>>>> the GC will pick them up. You never know when the GC will
>>>>>>> run, and you need a *lot* more memory,
>>>>>>
>>>>>> Those are misconceptions: there are systems that are completely
>>>>>> deterministic, others that are very predictable (e.g., GC is
>>>>>> schedulable in particular time slots, won't exceed given 
>>>>>> percentage of
>>>>>> CPU time, etc.), and systems that don't need much additional memory.
>>>>>>
>>>>>> There even are systems that combine predictability with low memory
>>>>>> overhead.
>>>>>
>>>>> All that is true. None of it invalidates what I said.
>>>>>
>>>>>>> so it's not a good way to get the most out of an MCU.
>>>>>>
>>>>>> I would say it it depends on the system.
>>>>>> My position is that GC has no place in a small system.
>>>>>
>>>>> Thanks for confirming my position.
>>>>
>>>> Well, given that dynamic allocation has no place in small systems 
>>>> either, GC is a bit of a non-issue. ;)
>>>>
>>>>>
>>>>>> OTOH, if you're talking about a complex
>>>>>> system with 32-bit controller and 100s of KB (or more) of RAM ...
>>>>>
>>>>> Then you have resources in such excess that *you don't need*
>>>>> to get the best out of it. Exactly what I said, in other words.
>>>>
>>>> Until it's been running long enough that the heap is fragmented into 
>>>> tiny, tiny bits.
>>>
>>> Modern generational GC compacts the heap quite effectively.
>>> The only real difficulties are (a) doing that unobtrusively
>>> and (b) being certain that you won't ever run out of memory
>>> due to leaks.
>>
>> I assume that you haven't got a lot of aliased pointers running round 
>> your code!
> 
> Generational GC relies on being able to move things between heaps,
> so object handles cannot be pointers (or rather, must be indirect).
> Languages that do it don't allow you to see the pointer as a number.
> ... another reason why you can't get the most out of the hardware.

Well, if nanny won't let you play with sharp objects, I guess it's hard 
to carve the beef. ;)

Cheers

Phil Hobbs

-- 
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

Thread

Embedded platforms for beginners? Elof Huang <elof.huang@runbox.com> - 2017-09-01 14:07 +0800
  Re: Embedded platforms for beginners? Jack <jack4747@gmail.com> - 2017-08-31 23:22 -0700
  Re: Embedded platforms for beginners? rickman <gnuarm@gmail.com> - 2017-09-01 04:10 -0400
  Re: Embedded platforms for beginners? Clifford Heath <no.spam@please.net> - 2017-09-01 21:49 +1000
    Re: Embedded platforms for beginners? Elof Huang <elof.huang@runbox.com> - 2017-09-02 11:57 +0800
      Re: Embedded platforms for beginners? Clifford Heath <no.spam@please.net> - 2017-09-02 18:25 +1000
        Re: Embedded platforms for beginners? Elof Huang <elof.huang@runbox.com> - 2017-09-03 15:37 +0800
          Re: Embedded platforms for beginners? Clifford Heath <no.spam@please.net> - 2017-09-03 17:54 +1000
          Re: Embedded platforms for beginners? rickman <gnuarm@gmail.com> - 2017-09-03 13:49 -0400
    Re: Embedded platforms for beginners? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-09-02 11:41 -0400
      Re: Embedded platforms for beginners? Clifford Heath <no.spam@please.net> - 2017-09-03 09:44 +1000
        Re: Embedded platforms for beginners? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-09-02 20:39 -0400
          Re: Embedded platforms for beginners? Clifford Heath <no.spam@please.net> - 2017-09-03 11:16 +1000
        Re: Embedded platforms for beginners? Paul Rubin <no.email@nospam.invalid> - 2017-09-02 18:21 -0700
          Re: Embedded platforms for beginners? Clifford Heath <no.spam@please.net> - 2017-09-03 14:26 +1000
            Re: Embedded platforms for beginners? rickman <gnuarm@gmail.com> - 2017-09-03 02:14 -0400
              Re: Embedded platforms for beginners? Clifford Heath <no.spam@please.net> - 2017-09-03 17:52 +1000
                Re: Embedded platforms for beginners? rickman <gnuarm@gmail.com> - 2017-09-03 13:50 -0400
                Re: Embedded platforms for beginners? Paul Rubin <no.email@nospam.invalid> - 2017-09-03 22:20 -0700
                Re: Embedded platforms for beginners? rickman <gnuarm@gmail.com> - 2017-09-05 22:06 -0400
                Re: Embedded platforms for beginners? Clifford Heath <no.spam@please.net> - 2017-09-06 12:21 +1000
                Re: Embedded platforms for beginners? rickman <gnuarm@gmail.com> - 2017-09-05 22:42 -0400
                Re: Embedded platforms for beginners? Clifford Heath <no.spam@please.net> - 2017-09-06 14:26 +1000
                Re: Embedded platforms for beginners? rickman <gnuarm@gmail.com> - 2017-09-06 01:20 -0400
                Re: Embedded platforms for beginners? George Neuner <gneuner2@comcast.net> - 2017-09-03 15:58 -0400
                Re: Embedded platforms for beginners? Clifford Heath <no.spam@please.net> - 2017-09-04 08:00 +1000
                Re: Embedded platforms for beginners? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-09-03 19:13 -0400
                Re: Embedded platforms for beginners? Clifford Heath <no.spam@please.net> - 2017-09-04 09:58 +1000
                Re: Embedded platforms for beginners? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-09-03 20:16 -0400
                Re: Embedded platforms for beginners? Clifford Heath <no.spam@please.net> - 2017-09-04 15:13 +1000
                Re: Embedded platforms for beginners? Paul Rubin <no.email@nospam.invalid> - 2017-09-03 22:24 -0700
                Re: Embedded platforms for beginners? Clifford Heath <no.spam@please.net> - 2017-09-04 15:55 +1000
                Re: Embedded platforms for beginners? David Brown <david.brown@hesbynett.no> - 2017-09-05 14:15 +0200
                Re: Embedded platforms for beginners? George Neuner <gneuner2@comcast.net> - 2017-09-05 12:35 -0400
                Re: Embedded platforms for beginners? Rob Gaddi <rgaddi@highlandtechnology.invalid> - 2017-09-05 10:02 -0700
                Re: Embedded platforms for beginners? Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-09-05 18:13 +0100
                Re: Embedded platforms for beginners? David Brown <david.brown@hesbynett.no> - 2017-09-06 10:24 +0200
                Re: Embedded platforms for beginners? Paul Rubin <no.email@nospam.invalid> - 2017-09-05 17:10 -0700
                Re: Embedded platforms for beginners? David Brown <david.brown@hesbynett.no> - 2017-09-06 09:57 +0200
                Re: Embedded platforms for beginners? Paul Rubin <no.email@nospam.invalid> - 2017-09-05 16:57 -0700
                Re: Embedded platforms for beginners? Paul Rubin <no.email@nospam.invalid> - 2017-09-05 16:54 -0700
                Re: Embedded platforms for beginners? Clifford Heath <no.spam@please.net> - 2017-09-06 12:31 +1000
                Re: Embedded platforms for beginners? Paul Rubin <no.email@nospam.invalid> - 2017-09-05 19:42 -0700
                Re: Embedded platforms for beginners? David Brown <david.brown@hesbynett.no> - 2017-09-05 10:16 +0200
                Re: Embedded platforms for beginners? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-09-05 16:56 -0400
                Re: Embedded platforms for beginners? Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-09-04 10:46 +0100
                Re: Embedded platforms for beginners? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-09-05 17:09 -0400
                Re: Embedded platforms for beginners? Paul Rubin <no.email@nospam.invalid> - 2017-09-05 19:35 -0700
                Re: Embedded platforms for beginners? Clifford Heath <no.spam@please.net> - 2017-09-06 12:40 +1000
                Re: Embedded platforms for beginners? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-09-06 00:42 -0400
                Re: Embedded platforms for beginners? Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-09-06 08:55 +0100
                Re: Embedded platforms for beginners? Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-09-06 08:45 +0100
                Re: Embedded platforms for beginners? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-09-07 20:23 -0400
                Re: Embedded platforms for beginners? Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-09-08 08:42 +0100
                Re: Embedded platforms for beginners? David Brown <david.brown@hesbynett.no> - 2017-09-08 12:07 +0200
                Re: Embedded platforms for beginners? Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-09-08 11:40 +0100
                Re: Embedded platforms for beginners? David Brown <david.brown@hesbynett.no> - 2017-09-08 13:24 +0200
                Re: Embedded platforms for beginners? Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-09-08 13:36 +0100
                Re: Embedded platforms for beginners? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-09-09 13:16 -0400
                Re: Embedded platforms for beginners? Les Cargill <lcargill99@comcast.com> - 2017-09-10 08:53 -0500
                Re: Embedded platforms for beginners? Dimiter_Popoff <dp@tgi-sci.com> - 2017-09-10 20:18 +0300
                Re: Embedded platforms for beginners? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-09-11 21:24 -0400
                Re: Embedded platforms for beginners? Les Cargill <lcargill99@comcast.com> - 2017-09-15 22:22 -0500
                Re: Embedded platforms for beginners? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-09-18 11:26 -0400
                Re: Embedded platforms for beginners? Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-09-18 18:26 +0100
                Re: Embedded platforms for beginners? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-09-19 14:27 -0400
                Re: Embedded platforms for beginners? Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-09-18 18:24 +0100
                Re: Embedded platforms for beginners? Paul Rubin <no.email@nospam.invalid> - 2017-09-03 22:30 -0700
                Re: Embedded platforms for beginners? Clifford Heath <no.spam@please.net> - 2017-09-04 15:51 +1000
            Re: Embedded platforms for beginners? Paul Rubin <no.email@nospam.invalid> - 2017-09-03 22:04 -0700
      Re: Embedded platforms for beginners? kristoff <kristoff@skypro.be> - 2017-09-05 17:56 +0200
        Re: Embedded platforms for beginners? Luke A. Guest <laguest@archeia.com> - 2017-09-10 17:10 +0100
  Re: Embedded platforms for beginners? tarjei99@gmail.com - 2017-09-10 05:49 -0700
    Re: Embedded platforms for beginners? Les Cargill <lcargill99@comcast.com> - 2017-09-10 09:03 -0500

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