[Tinyos-devel] ctp vs other radio clients

[Branislav Kusy]

i did wire directly to ActiveMessageC. i'll try with AMSenderC on 
monday. pretty sure this was the problem.

brano

Philip Levis wrote:
> Well, wiring directly to ActiveMessageC would definitely be a problem! 
> Regardless, it looks like ctp needs to handle busy better. I'll look 
> deeper. 
> 
> 
> Phil
> 
> On Dec 6, 2008, at 9:18 AM, "Geoffrey Werner-Allen" 
> <werner at eecs.harvard.edu <mailto:werner at eecs.harvard.edu>> wrote:
> 
>> Doesn't the queue only get put on the path if the component wires to 
>> AMSenderC? What happens if, as Brany asked, something like FTSP wires 
>> straight down to (essentially) CC2420ActiveMessageC.nc (which it does 
>> through TimeSyncC.nc)? Anything sent below the queue won't get 
>> properly serialized, right? This could cause an unexpected EBUSY 
>> return in AMQueueImplP.nc if the stack is busy with somthing inserted 
>> below the queue.
>>
>> Best,
>>
>> -gwa-
>>
>> geoffrey werner-allen :: 617.694.7261 :: 
>> <http://www.eecs.harvard.edu/~werner>www.eecs.harvard.edu/~werner 
>> <http://www.eecs.harvard.edu/~werner>
>>
>>
>> On Sat, Dec 6, 2008 at 12:15 PM, Philip Levis < 
>> <mailto:pal at cs.stanford.edu>pal at cs.stanford.edu 
>> <mailto:pal at cs.stanford.edu>> wrote:
>>
>>
>>     On Dec 6, 2008, at 9:05 AM, Geoffrey Werner-Allen wrote:
>>
>>         I'm pretty sure there IS one SendState and this was my concern
>>         exactly, although Om states it more clearly.
>>
>>         Best,
>>
>>
>>     There is only one instance of StateC, but why does this matter?
>>     Let's look at the queue code:
>>
>>
>>            if (current >= numClients) { // queue empty
>>                error_t err;
>>                am_id_t amId = call AMPacket.type(msg);
>>                am_addr_t dest = call AMPacket.destination(msg);
>>
>>                dbg("AMQueue", "%s: request to send from %hhu (%p):
>>     queue empty\n", __FUNCTION__, clientId, msg);
>>                current = clientId;
>>
>>                err = call AMSend.send[amId](dest, msg, len);
>>                if (err != SUCCESS) {
>>                    dbg("AMQueue", "%s: underlying send failed.\n",
>>     __FUNCTION__);
>>                    current = numClients;
>>                    queue[clientId].msg = NULL;
>>
>>                }
>>                return err;
>>            }
>>            else {
>>                dbg("AMQueue", "AMQueue: request to send from %hhu
>>     (%p): queue not empty\n", clientId, msg);
>>            }
>>            return SUCCESS;
>>
>>     AMQueueImplP (of which there is a single instance, it uses
>>     uniqueCount() to scale its state) only calls the lower AMSend if
>>     the queue is empty. If the queue is not empty, this means there is
>>     an outstanding send, so it waits for the underlying sendDone.
>>
>>     Phil
>>
>>
> 
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