On 8/7/06, Avinash Sridharan <[EMAIL PROTECTED]> wrote:
The Problem: Due to contention at high data rates (when the timer size is close to 10ms) there is queueing taking place at the sender and the logging is also happening at a very fast rate. It turns out that at such a high rate when the commit call is made it blocks and does not return. It seems at these high data rates tinyos deadlocks and is not able to execute any other code. More specifically I can observe this behavior at rates of 10ms and 11ms, as I go to lower rates the applications works fine. Also this behavior is erratic in the sense there are times when the logging at 10ms and 11ms works fine without blocking.
- Are you checking the error codes on calls to BlockWrite.write() and BlockWrite.commit(). Are they all returning success, even when your app "deadlocks"? - Does the issue only happen when you call BlockWrite.commit() and not when writing data to the flash?
Questions: a> Could somebody clarify the deadlock behavior I am observing ( Or if it is even deadlock) and if someone else has observed this behavior ?
Can you say more about your statement "do a read on the flash (around 10 lines of data) and immediately the application starts sending"? Is this sending a radio packet to tell it to read some data? Are you reprogramming it to read some data? Clicking a button?
b> Are there some performance measures as to how fast and how much data can we write and commit on the block storage device ? This will help define the capacity of the system better.
Taking into account hardware limits, the ST chip states that it can take up to 5 ms to do a write for a given page. If you're writing across N pages, then it can take N*5ms. The commit implementation on the ST chip simply posts a couple tasks, so that operation should take significantly less time than writing. Also, would it be possible to take a look at the code? -- Jonathan W. Hui [EMAIL PROTECTED] http://www.cs.berkeley.edu/~jwhui/ _______________________________________________ Tinyos-help mailing list [email protected] https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
