Hi Andris, Ok, thank you for the valuable information!
Martin -------- Original Message -------- Subject: Re: [Tinyos-help] Managing table with neighbors - dynamic allocation From: András Bíró <bband...@gmail.com> To: Martin Stehlik <stehli...@atlas.cz> Cc: tinyos-help@millennium.berkeley.edu Date: Monday, November 21, 2011 14:46:44 > Hi Martin, > > After compilation tinyos prints the ram/rom usage of tha application > with the gnu size util (or avr-size or msp430-size, depending on your > platform). As I mentioned earlier ram is not really precise, I usually > leave about 10% of the memory "free" (available for stack), and I > never had problem with that method. > > Andris > > 2011/11/21 Martin Stehlik<stehli...@atlas.cz>: >> Hi Andris, >> >> Thank you. I know the overall amount of memory but I do not know how much is >> remaining (can be used) for the table. Nevertheless, I have some idea now. >> The main point was to ensure myself that using dynamic allocation is not >> good method and I should avoid it. >> >> Thank you very much. >> Martin >> >> -------- Original Message -------- >> Subject: Re: [Tinyos-help] Managing table with neighbors - dynamic >> allocation >> From: András Bíró<bband...@gmail.com> >> To: Martin Stehlik<stehli...@atlas.cz> >> Cc: tinyos-help@millennium.berkeley.edu >> Date: Monday, November 21, 2011 14:25:56 >> >>> Hi Martin, >>> >>> The memory size should be in the datasheets. If it's not in the >>> platform datasheet, then check the microcontroller's datasheet (it's >>> usually about 2-10kB). >>> >>> Andris >>> >>> On Mon, Nov 21, 2011 at 2:15 PM, Martin Stehlik<stehli...@atlas.cz> >>> wrote: >>>> >>>> Hi Andris, >>>> >>>> Thank you for your answer! You understood correctly and I am aware of >>>> the reason why I should not allocate the memory dynamically. >>>> >>>> Thus, I will probably set the size of the data at compilation-time. Is >>>> there any method how I can find out the available amount of the hardware >>>> memory? >>>> >>>> Thank you very much. >>>> Martin >>>> >>>> -------- Original Message -------- >>>> Subject: Re: [Tinyos-help] Managing table with neighbors - dynamic >>>> allocation >>>> From: András Bíró<bband...@gmail.com> >>>> To: Martin Stehlik<stehli...@atlas.cz> >>>> Cc: tinyos-help@millennium.berkeley.edu >>>> Date: Monday, November 21, 2011 13:39:37 >>>> >>>>> Hi Martin, >>>>> >>>>> If I understood correctly, the reason for not recommending dynamic >>>>> memory in tinyos is that there's no memory protection at all. Your >>>>> data memory grows from one side of the memory, and the stack grows >>>>> from the other side, if they're overlap, that could cause a hardly >>>>> understandable crash. Using dynamic memory allocation causes >>>>> fragmentation in data memory, therefor it's unpredictable when will >>>>> they overlap. >>>>> So, most peaple sets the size of such data compilation-time, to the >>>>> maximum which fits in the hardware memory (warning: the size util, >>>>> which prints the rom/ram usage after tinyos compile is not really >>>>> accurate, probably because it doesn't count the stack). >>>>> >>>>> Andris >>>>> >>>>> On Mon, Nov 21, 2011 at 1:13 PM, Martin Stehlik<stehli...@atlas.cz> >>>>> wrote: >>>>>> >>>>>> Hello! >>>>>> >>>>>> Is anyone experienced with dynamic allocation of tables (arrays) in >>>>>> TinyOS? I need to store a table of neighbors in each of the nodes >>>>>> containing some information like RSSI of the messages coming from the >>>>>> neighbors etc. I do not know the number of neighbors in advance (I can >>>>>> discover them using some "Hello" message etc. whenever). It means that >>>>>> the table should grow dynamically once a new neighbor is discovered. >>>>>> >>>>>> My first idea was using structures and dynamically allocate new items >>>>>> in >>>>>> the list (actually an implementation of linked list). Then I read in >>>>>> mailing list and in documentation that the usage of malloc etc. is not >>>>>> recommended. I have also found several data structures like queue or >>>>>> pool but they do not seem to be suitable for my purpose. I could also >>>>>> allocate the memory statically during compile time but I am afraid it >>>>>> would be wasting of memory and the application would not be robust for >>>>>> high amount of neighbors. >>>>>> >>>>>> Can anyone suggest me some suitable and effective solution for my >>>>>> problem? >>>>>> >>>>>> I will welcome any answer or suggestion very much! >>>>>> >>>>>> Best, >>>>>> Martin >>>>>> _______________________________________________ >>>>>> Tinyos-help mailing list >>>>>> Tinyos-help@millennium.berkeley.edu >>>>>> >>>>>> https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help >>>>>> >>>> _______________________________________________ >>>> Tinyos-help mailing list >>>> Tinyos-help@millennium.berkeley.edu >>>> https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help >>>> >> _______________________________________________ Tinyos-help mailing list Tinyos-help@millennium.berkeley.edu https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
