Respected Sir,
Thanks a lot for replying. It really means a lot to me.
I was indeed overwriting some memory in the code, which I have fixed.
So for the time being got rid of segmentation fault.
But the main problem still persists.
I have attached the code snippet in the file 'details.txt'. Please
take a look whenever convenient for you.
Here nodes 1 and 2 send data to the leader node 3 which takes average
of 2 packets and sends this to base station.
Now the code runs in an infinite loop because 3 keeps on getting data,
calculates correct average and sends to base station. But the base
station isnt receiving any data. How do I make it receive ? The event
should be triggered on its own isnt it?
Or if you can suggest some other way of doing the same thing ?
I hope to hear again from you.I am sure your pointers will help me
progress further.
Thanking you in advance.
Regards,
Kiraneet
On 11/26/09, Paul Johnson <[email protected]> wrote:
> Kiraneet,
>
> As stated before, tinyos-1.x hasn't been in development for a few years,
> so it's unlikely that many people on the list are going to be able to
> give you much support. Please include at least the important code
> segments that you modified/created, otherwise, I can only guess in the
> dark about the problem.
>
> If TOSSIM is segfaulting, then it's very likely that you have some
> memory corruption issues. (unless there were some issues in TOSSIM for 1.x)
>
> -Paul
>
> Kiraneet sharma wrote:
>> Hello everyone...
>>
>> I had asked this query earlier but since I got no reply yet..I am
>> trying to explain the problem in detail.If someone could help me I
>> would be really grateful.
>>
>> I am trying to simulate data aggregation in tinyos-1.x
>>
>> I have 6 nodes:
>> 1 and 2 send their data to their leader i.e. node 3..similarly 4 and 5
>> send data to node 6..
>> after about collecting three readings nodes 3 and 6 calculate the
>> average and send the aggregated data to base station i.e. node 0.
>>
>>
>> This thing is done entirely in simulation and works well for ONE time
>> only.
>> After that nodes 3 and 6 continue to correctly calculate the average
>> and send data to base station,however it is never received.
>>
>> The thing is that when I am trying to implement the same logic without
>> any average calculation then it works fine.
>>
>> To implement this entire logic I have added a few statements in
>> receive and send in AMStandard.
>>
>> So is it possible that multiple sends are done consecutively and so
>> packet collision occurs, causing the packets to be dropped and not
>> being received by base station?
>>
>> At times the program terminates with a segmentation fault ?
>> Any pointers where should I do this averaging thing ? Where does the
>> problem lie?
>>
>> Thanks a lot in advance..
>>
>> Hope to hear from you..
>>
>> Best regards,
>> Kiraneet
>>
>> ------------------------------------------------------------------------
>>
>> _______________________________________________
>> Tinyos-help mailing list
>> [email protected]
>> https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
>
Within AMStandard.nc which is located in opt/tinyos-1.x/tos/system/
command result_t SendMsg.send[uint8_t id](uint16_t addr, uint8_t length,
TOS_MsgPtr data) {
if (!state) {
...
}
if (!(post sendTask())) {
...
}
else
{
/*This I have added*/
/*If the packet is being sent to leader node 3, then insert required
data
this is according to my appln needs, so am just writing here mydata
for better understanding*/
if(addr==3)
{
if(packets_recv3<2)
{
packets_send3++;
/*Depending on odd or even packets different data is to be
sent*/
switch(packets_send3%2)
{
case 0: data->data[0]=mydata1;
data->data[1]=mydata2;
printf("Data populated 1 case\n");
break;
case 1: data->data[0]=mydata3;
data->data[1]=mydata4;
printf("Data populated 2 case\n");
break;
default: break;
}
}
else
packets_send3=0;
}
/*If packet is for base station then put the average calculated in data
packets*/
else if(addr==0)
{
data->data[0]=avg3_x;
data->data[1]=avg3_y;
avg3_x=0;
avg3_y=0;
}
//This is the same as in original file
buffer = data;
data->length = length;
data->addr = addr;
data->type = id;
buffer->group = TOS_AM_GROUP;
}
return SUCCESS;
}
...
TOS_MsgPtr received(TOS_MsgPtr packet) __attribute__ ((C, spontaneous)) {
...
if (packet->crc == 1 && // Uncomment this line to check crcs
packet->group == TOS_AM_GROUP &&
(packet->addr == TOS_BCAST_ADDR ||
packet->addr == addr))
{
/*These 3 lines are added here in the same form as it is in IntToRfmM.nc*/
struct TOS_Msg data_avg3;
IntMsg *message = (IntMsg *)data_avg3.data;
message->src = TOS_LOCAL_ADDRESS;
/*If packet is received by leader node 3*/
if(packet->addr==3)
{
/*No of packets received is less than 2 we shall just add the values and store
and if this counter becomes 2 then calculate average
so aggregating only 2 packets here*/
if(packets_recv3<2)
{
packets_recv3++;
avg3_x+=packet->data[0];
avg3_y+=packet->data[1];
}
if(packets_recv3==2)
{
avg3_x/=2;
avg3_y/=2;
//send to base station
packets_recv3=0;
packets_send3=0;
call SendMsg.send[4](0,sizeof(IntMsg),&data_avg3);
}
}
/*Now if instead of above code I write
if(packet->addr==3)
call SendMsg.send[4](0,8,packet);
then it is working perfectly fine
i.e. whatever packets 1 and 2 send are received correctly by 3
and forwarded to 0 and again correctly received by base station.
*/
else
{
// base station does it's processing
...
}
_______________________________________________
Tinyos-help mailing list
[email protected]
https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
