[Tinyos-devel] FTSP testing result

[Thomas Schmid]

The current version of FTSP has a quantization bug in it while
calculating the sum of squares. Therefore, the time synchronization
error is always around +/- 4ms. I attached a patch to this email which
fixes this. Not sure if this helps with your problems though.

How does the topology of tutornet look like? are all the nodes within
radio range of each other? Or how many neighbors are there on average?

Cheers,

Thomas

On Mon, Feb 2, 2009 at 11:18 PM, Omprakash Gnawali <gnawali at usc.edu> wrote:
> I ran FTSP for a few hours on Tutornet and the result is not good. The
> nodes go out-of-sync frequently enough to make the system unusable.
>
> Setup: I updated my tos directory from CVS head earlier today. I
> changed tests/TestFtsp to log FTSP time every 10s. 56 nodes total.
> "PFLAGS += -DTIMESYNC_RATE=30" added to the Makefile.
>
> Here are some results:
> http://enl.usc.edu/~om_p/net2/ftsp/
>
> Every 10s, for each node, I plot a point on the first graph if the
> getGlobalTime() returns a FAIL indicating unavailability of global
> time. If there are no dots on the graph, it would mean the nodes have
> a valid global time at all times.
>
> With Trickle timer, the results are worse, but maybe we should fix the
> periodic case before we get to Trickle. Turns out the
> consistency/PULL-bit is more complex than I had thought but it should
> be doable.
>
> - om_p
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-- 
"Don't complain; Just work harder" - Randy Pausch

Thomas Schmid, Ph.D. Candidate
Networked & Embedded Systems Laboratory (NESL)
University of California, Los Angeles (UCLA)
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