[Tinyos-devel] lost packets from PC to the mote

[Razvan Musaloiu-E.]

Hi!

On Sat, 19 Apr 2008, Razvan Musaloiu-E. wrote:

> Hi!
>
> On Sat, 19 Apr 2008, Vlado Handziski wrote:
>
>> It is a known behavior for which many hypothesis have been made, but no one
>> has nailed the bug/problem until now. You can dig through the  core WG notes
>> for some more info on the issues like the different preference to sending
>> mote->pc direction, etc. Ben has looked into this and it seems it is not a
>> queue overflow problem. He also experimented with making the ISR reentrant
>> without noticeable improvement.
>
> Thanks for the quick reply. I guess some of the notes you are talking
> about are these:
> 	http://tinyos.stanford.edu:8000/TinyOS_2.x_WG/05.16.2007

Some more details: I run the same test code on micaz (on which the 
baudrate is 57600) and no packets were lost. I also lowered the baudrate 
to 57600 for telosb and it also stop losing packets. I only tested with 
low (1 packet/s) data rates from PC to the mote.

Question for Ben: did you also notice this?

--
Razvan ME

>> On Sat, Apr 19, 2008 at 3:47 AM, Razvan Musaloiu-E. <razvanm at cs.jhu.edu>
>> wrote:
>>
>>> Hi!
>>>
>>> I just noticed that when a mote sends a lot of packets to a the PC, the
>>> packets from the PC to the mote doesn't go reach the user application layer
>>> some of the time. In the attached archive there is a test program that is
>>> exposing this. The mote program is sending packets back-to-back while the PC
>>> program (in Java) is receiving the packets and sends to the mote one packets
>>> each second. I run the program on telosb in the following way:
>>>
>>> (console 1)$ ./sf 9001 /dev/ttyUSB0 115200
>>> (console 2)$ java StressSerialTest -comm sf at localhost:9001
>>>
>>> The mote is toggling the blue led each time it receives a packet and it
>>> should change state each time the RX led from the USB blinks. This doesn't
>>> always happen: the RX led indicates a receive but the blue doesn't always
>>> change its state. The (console 1) also shows lines like this:
>>>        Note: write failed
>>>        Note: write failed
>>>        Note: write failed
>>>        Note: write failed
>>>
>>> Did anyone else notice this behavior?
>>>
>>> --
>>> Razvan ME
>>>
>>>
>>
>