Hi,
I'll try to answer some of your questions based on my experience.
> 1. I note that #entries in the regression table never reaches 8.
Starting from 0 it goes on to 1,2,3,4,5 and then > back to 1. Why this
is so I cannot understand.
If your nodes are flushing the table, you should probabily try increasing
"ENTRY_VALID_LIMIT" value.
This value depends on the *platform* and *frequency* that you are using.
> My doubt is - I expected that skew would become ~constant after some
time(i.e after the best fit line has been > drawn succesfully). Instead
I see that skew is continually varying. Why this is so ?
This is probabily because the sync point is keep changing.
Remember that after the table fills 8 entries, it will keep replace the
old entry with a new one.
Since timesync cannot be perfect (this is why we are doing timesync :-)),
it is reasonable that the skew changes continuously.
>3. Even after is_synched = 1, gobal clock and local clock have time
difference.
> For example Globalclock= 244808120 Local clock=241417105
> Due to what is this difference ?
Sure!!
Globaltime and localtime will be different in all nodes except the root,
since all nodes are syncing to the global time (except the root)
I think you are confused about what 'localtime' is.
Local time is the time maintained locally in ALL nodes.
Global time is the localtime of the root node
that all non-root nodes are trying to guess.
10 448 411352693 411352693 0.0 1 10 11 0
10 448 411352693 411352693 0.0 1 10 11 0
11 449 412255067 408864393 -2.0105676E-6 0 10 10 1
11 449 412255067 408864393 -2.0105676E-6 0 10 10 1
In the log below,
I can see that you have two nodes 10 and 11,
and 10 is the root node,
and 11 is trying to *know* the time of node 10.
But the strange thing is that only one node is responding to each poller
beacon.
Node 10 replied to beacon 448, but not node 11.
Node 11 replied to beacon 449, but not node 10.
This is weird.... since both node should reply to the same beacon.
It should be something like....
10 *451* 414048342 414048342 0.0 1 10 11 0
11 *451* 414048342 410xxxxxx -2.0105676E-6 0 10 10 1
My guess is that there is some bug in your program,
which is causing packet collision, or some kind of packet corruption.
Please have a look at the 'TimeSyncDebugger" part,
where you reply to the beacon from the Poller.
Two nodes should not try at the same time (-> collision)
Thank you.
Jeongyeup Paek
Embedded Networks Laboratory
Department of Computer Science
University of Southern California
Sharmistha Maitra wrote:
Dear All and Santosh,
Thanks for your help. Now I am getting 'sensible' time synch data
skew,is_synched etc :-)
I still have some questions related to the timesynch data (see below) :
My test scenario
-----------------
1 base station, 1 polling station, two nodes (nodeid 10 and 11) are
being time synched.10 is the timesynch root.
-------------------------------------------------------------------------
1. I note that #entries in the regression table never reaches 8.
Starting from 0 it goes on to 1,2,3,4,5 and then back to 1. Why this
is so I cannot understand.
---------------------------------------------------------------------------
2. When there is 1 entry in the regression table, skew shows 0.0. That
is quite reasonable since atleast two points needed to draw the best
fit line. After that as entries fill up the regression table, skew
changes. This is also OK since slope of the best fit line keeps on
changing as more and more points are added.
I know that skew = (Global clock freq/Local clock freq - 1). I am
assuming that the freq of the oscillators hasnt changed within the
short time span (5 mins) that I tested.
My doubt is - I expected that skew would become ~constant after some
time(i.e after the best fit line has been drawn succesfully). Instead
I see that skew is continually varying. Why this is so ?
--------------------------------------------------------------------------------------
3. Even after is_synched = 1, gobal clock and local clock have time
difference.
For example Globalclock= 244808120 Local clock=241417105
Due to what is this difference ?
DATA (10, 11 --> nodeids)
=======
10 292 270921570 270921570 0.0 1 10 6 0
10 292 270921570 270921570 0.0 1 10 6 0
11 293 271818377 268427313 -2.7584806E-6 0 10 5 1 <----#entries in
regression table
11 293 271818377 268427313 -2.7584806E-6 0 10 5 1
10 295 273617549 273617549 0.0 1 10 6 0
10 295 273617549 273617549 0.0 1 10 6 0
11 296 274513181 271122125 -2.7584806E-6 0 10 5 1
11 296 274513181 271122125 -2.7584806E-6 0 10 5 1
10 298 276320632 276320632 0.0 1 10 6 0
10 298 276320632 276320632 0.0 1 10 6 0
11 299 277222420 273831371 -2.7584806E-6 0 10 5 1
11 299 277222420 273831371 -2.7584806E-6 0 10 5 1
10 301 279021170 279021170 0.0 1 10 6 0
10 301 279021170 279021170 0.0 1 10 6 0
11 302 279922271 276531230 -2.7584806E-6 0 10 5 1
11 302 279922271 276531230 -2.7584806E-6 0 10 5 1
10 304 281724564 281724564 0.0 1 10 6 0
10 304 281724564 281724564 0.0 1 10 6 0
11 305 282619642 279228608 -2.7584806E-6 0 10 5 1
11 305 282619642 279228608 -2.7584806E-6 0 10 5 1
10 307 284423509 284423509 0.0 1 10 6 0
10 307 284423509 284423509 0.0 1 10 6 0
11 309 286226037 282835013 -2.7584806E-6 0 10 5 1
11 309 286226037 282835013 -2.7584806E-6 0 10 5 1
10 310 287117582 287117582 0.0 1 10 6 0
10 310 287117582 287117582 0.0 1 10 6 0
11 311 288024137 284633118 -2.7584806E-6 0 10 5 1
11 311 288024137 284633118 -2.7584806E-6 0 10 5 1
10 313 289826327 289826327 0.0 1 10 6 0
10 313 289826327 289826327 0.0 1 10 6 0
11 314 290720985 287329973 -2.7584806E-6 0 10 5 1
11 314 290720985 287329973 -2.7584806E-6 0 10 5 1
10 316 292529120 292529120 0.0 1 10 6 0
10 316 292529120 292529120 0.0 1 10 6 0
11 317 293420833 290029829 -2.7584806E-6 0 10 5 1
11 317 293420833 290029829 -2.7584806E-6 0 10 5 1
10 319 295226765 295226765 0.0 1 10 6 0
10 319 295226765 295226765 0.0 1 10 6 0
11 320 296126902 292735905 -2.7584806E-6 0 10 5 1
11 320 296126902 292735905 -2.7584806E-6 0 10 5 1
10 322 297927631 297927631 0.0 1 10 7 0
10 322 297927631 297927631 0.0 1 10 7 0
11 323 298826013 295434949 -7.405064E-8 0 10 6 2
11 323 298826013 295434949 -7.405064E-8 0 10 6 2
10 325 300631482 300631482 0.0 1 10 7 0
10 325 300631482 300631482 0.0 1 10 7 0
11 326 301521345 298130281 -7.405064E-8 0 10 6 2
11 326 301521345 298130281 -7.405064E-8 0 10 6 2
10 328 303330613 303330613 0.0 1 10 7 0
10 328 303330613 303330613 0.0 1 10 7 0
11 329 304220120 300829056 -7.405064E-8 0 10 6 2
11 329 304220120 300829056 -7.405064E-8 0 10 6 2
10 331 306032184 306032184 0.0 1 10 7 0
10 331 306032184 306032184 0.0 1 10 7 0
11 332 306925525 303534461 -7.405064E-8 0 10 6 2
11 332 306925525 303534461 -7.405064E-8 0 10 6 2
10 334 308722332 308722332 0.0 1 10 7 0
10 334 308722332 308722332 0.0 1 10 7 0
11 335 309630865 306239801 -7.405064E-8 0 10 6 2
11 335 309630865 306239801 -7.405064E-8 0 10 6 2
10 337 311423996 311423996 0.0 1 10 7 0
10 337 311423996 311423996 0.0 1 10 7 0
11 338 312329376 308938313 -7.405064E-8 0 10 6 2
11 338 312329376 308938313 -7.405064E-8 0 10 6 2
10 340 314123192 314123192 0.0 1 10 7 0
10 340 314123192 314123192 0.0 1 10 7 0
11 341 315032301 311641238 -7.405064E-8 0 10 6 2
11 341 315032301 311641238 -7.405064E-8 0 10 6 2
10 343 316835397 316835397 0.0 1 10 7 0
10 343 316835397 316835397 0.0 1 10 7 0
11 344 317725877 314334814 -7.405064E-8 0 10 6 2
11 344 317725877 314334814 -7.405064E-8 0 10 6 2
10 346 319526792 319526792 0.0 1 10 7 0
10 346 319526792 319526792 0.0 1 10 7 0
11 347 320433383 317042320 -7.405064E-8 0 10 6 2
11 347 320433383 317042320 -7.405064E-8 0 10 6 2
10 349 322232302 322232302 0.0 1 10 7 0
10 349 322232302 322232302 0.0 1 10 7 0
11 350 323134004 319742941 -7.405064E-8 0 10 6 2
11 350 323134004 319742941 -7.405064E-8 0 10 6 2
10 352 324932836 324932836 0.0 1 10 8 0
10 352 324932836 324932836 0.0 1 10 8 0
11 353 325825321 322434364 -2.351139E-6 0 10 7 3
11 353 325825321 322434364 -2.351139E-6 0 10 7 3
10 355 327626463 327626463 0.0 1 10 8 0
10 355 327626463 327626463 0.0 1 10 8 0
11 356 328529051 325138101 -2.351139E-6 0 10 7 3
11 356 328529051 325138101 -2.351139E-6 0 10 7 3
10 358 330333741 330333741 0.0 1 10 8 0
10 358 330333741 330333741 0.0 1 10 8 0
11 359 331227279 327836335 -2.351139E-6 0 10 7 3
11 359 331227279 327836335 -2.351139E-6 0 10 7 3
10 361 333036072 333036072 0.0 1 10 8 0
10 361 333036072 333036072 0.0 1 10 8 0
11 362 333932889 330541951 -2.351139E-6 0 10 7 3
11 362 333932889 330541951 -2.351139E-6 0 10 7 3
10 364 335733249 335733249 0.0 1 10 8 0
10 364 335733249 335733249 0.0 1 10 8 0
11 365 336627847 333236916 -2.351139E-6 0 10 7 3
11 365 336627847 333236916 -2.351139E-6 0 10 7 3
10 367 338434979 338434979 0.0 1 10 8 0
10 367 338434979 338434979 0.0 1 10 8 0
11 368 339337980 335947055 -2.351139E-6 0 10 7 3
11 368 339337980 335947055 -2.351139E-6 0 10 7 3
10 370 341141474 341141474 0.0 1 10 8 0
10 370 341141474 341141474 0.0 1 10 8 0
11 371 342031329 338640410 -2.351139E-6 0 10 7 3
11 371 342031329 338640410 -2.351139E-6 0 10 7 3
10 373 343833671 343833671 0.0 1 10 8 0
10 373 343833671 343833671 0.0 1 10 8 0
11 374 344732383 341341471 -2.351139E-6 0 10 7 3
11 374 344732383 341341471 -2.351139E-6 0 10 7 3
10 376 346537547 346537547 0.0 1 10 8 0
10 376 346537547 346537547 0.0 1 10 8 0
11 378 348330166 344939262 -2.351139E-6 0 10 7 3
11 378 348330166 344939262 -2.351139E-6 0 10 7 3
10 379 349243021 349243021 0.0 1 10 8 0
10 379 349243021 349243021 0.0 1 10 8 0
11 380 350130734 346739834 -2.351139E-6 0 10 7 3
11 380 350130734 346739834 -2.351139E-6 0 10 7 3
10 382 351940566 351940566 0.0 1 10 9 0
10 382 351940566 351940566 0.0 1 10 9 0
11 383 352838931 349448044 -2.451082E-6 1 10 8 4
11 383 352838931 349448044 -2.451082E-6 1 10 8 4
10 385 354634735 354634735 0.0 1 10 9 0
10 385 354634735 354634735 0.0 1 10 9 0
11 386 355544574 352153694 -2.451082E-6 1 10 8 4
11 386 355544574 352153694 -2.451082E-6 1 10 8 4
10 388 357343508 357343508 0.0 1 10 9 0
10 388 357343508 357343508 0.0 1 10 9 0
11 389 358235439 354844565 -2.451082E-6 1 10 8 4
11 389 358235439 354844565 -2.451082E-6 1 10 8 4
10 391 360038784 360038784 0.0 1 10 9 0
10 391 360038784 360038784 0.0 1 10 9 0
11 392 360933380 357542513 -2.451082E-6 1 10 8 4
11 392 360933380 357542513 -2.451082E-6 1 10 8 4
10 394 362735803 362735803 0.0 1 10 9 0
10 394 362735803 362735803 0.0 1 10 9 0
11 395 363643944 360253084 -2.451082E-6 1 10 8 4
11 395 363643944 360253084 -2.451082E-6 1 10 8 4
10 397 365443700 365443700 0.0 1 10 9 0
10 397 365443700 365443700 0.0 1 10 9 0
11 398 366344034 362953180 -2.451082E-6 1 10 8 4
11 398 366344034 362953180 -2.451082E-6 1 10 8 4
10 400 368147606 368147606 0.0 1 10 9 0
10 400 368147606 368147606 0.0 1 10 9 0
11 401 369040069 365649222 -2.451082E-6 1 10 8 4
11 401 369040069 365649222 -2.451082E-6 1 10 8 4
10 403 370841991 370841991 0.0 1 10 9 0
10 403 370841991 370841991 0.0 1 10 9 0
11 404 371739368 368348527 -2.451082E-6 1 10 8 4
11 404 371739368 368348527 -2.451082E-6 1 10 8 4
10 406 373539993 373539993 0.0 1 10 9 0
10 406 373539993 373539993 0.0 1 10 9 0
11 407 374441314 371050480 -2.451082E-6 1 10 8 4
11 407 374441314 371050480 -2.451082E-6 1 10 8 4
10 409 376237868 376237868 0.0 1 10 9 0
10 409 376237868 376237868 0.0 1 10 9 0
11 410 377145122 373754295 -2.451082E-6 1 10 8 4
11 410 377145122 373754295 -2.451082E-6 1 10 8 4
10 412 378950053 378950053 0.0 1 10 10 0
10 412 378950053 378950053 0.0 1 10 10 0
11 413 379839185 376448329 -2.0105676E-6 1 10 9 5
11 413 379839185 376448329 -2.0105676E-6 1 10 9 5
10 415 381644958 381644958 0.0 1 10 10 0
10 415 381644958 381644958 0.0 1 10 10 0
11 416 382554959 379164108 -2.0105676E-6 1 10 9 5
11 416 382554959 379164108 -2.0105676E-6 1 10 9 5
10 418 384351031 384351031 0.0 1 10 10 0
10 418 384351031 384351031 0.0 1 10 10 0
11 419 385243294 381852449 -2.0105676E-6 1 10 9 5
11 419 385243294 381852449 -2.0105676E-6 1 10 9 5
10 421 387048012 387048012 0.0 1 10 10 0
10 421 387048012 387048012 0.0 1 10 10 0
11 422 387948698 384557858 -2.0105676E-6 1 10 9 5
11 422 387948698 384557858 -2.0105676E-6 1 10 9 5
10 424 389745214 389745214 0.0 1 10 10 0
11 425 390642596 387251762 -2.0105676E-6 1 10 9 5
11 425 390642596 387251762 -2.0105676E-6 1 10 9 5
10 427 392443017 392443017 0.0 1 10 10 0
10 427 392443017 392443017 0.0 1 10 10 0
11 428 393347768 389956939 -2.0105676E-6 1 10 9 5
11 428 393347768 389956939 -2.0105676E-6 1 10 9 5
10 431 396044350 396044350 0.0 1 10 10 0
10 431 396044350 396044350 0.0 1 10 10 0
11 431 396043688 392652865 -2.0105676E-6 1 10 9 5
11 431 396043688 392652865 -2.0105676E-6 1 10 9 5
10 433 397847901 397847901 0.0 1 10 10 0
10 433 397847901 397847901 0.0 1 10 10 0
11 434 398744704 395353886 -2.0105676E-6 1 10 9 5
11 434 398744704 395353886 -2.0105676E-6 1 10 9 5
10 436 400543218 400543218 0.0 1 10 10 0
10 436 400543218 400543218 0.0 1 10 10 0
11 437 401449893 398059080 -2.0105676E-6 1 10 9 5
11 437 401449893 398059080 -2.0105676E-6 1 10 9 5
10 439 403252338 403252338 0.0 1 10 10 0
10 439 403252338 403252338 0.0 1 10 10 0
11 440 404154554 400763747 -2.0105676E-6 1 10 9 5
11 440 404154554 400763747 -2.0105676E-6 1 10 9 5
10 442 405962026 405962026 0.0 1 10 11 0
10 442 405962026 405962026 0.0 1 10 11 0
11 443 406849126 403458441 -2.0105676E-6 0 10 10 1<----#entries goes
back to 1 again
11 443 406849126 403458441 -2.0105676E-6 0 10 10 1
10 445 408650787 408650787 0.0 1 10 11 0
10 445 408650787 408650787 0.0 1 10 11 0
11 446 409548132 406157453 -2.0105676E-6 0 10 10 1
11 446 409548132 406157453 -2.0105676E-6 0 10 10 1
10 448 411352693 411352693 0.0 1 10 11 0
10 448 411352693 411352693 0.0 1 10 11 0
11 449 412255067 408864393 -2.0105676E-6 0 10 10 1
11 449 412255067 408864393 -2.0105676E-6 0 10 10 1
10 451 414048342 414048342 0.0 1 10 11 0
10 451 414048342 414048342 0.0 1 10 11 0
11 452 414956264 411565596 -2.0105676E-6 0 10 10 1
11 452 414956264 411565596 -2.0105676E-6 0 10 10 1
Thanks once again.
Sharmistha.
*----- Original Message -----*
*From*: santosh dwivedi <[EMAIL PROTECTED]> *Date*: Monday, December
19, 2005 7:22 pm *Subject*: Re: [Tinyos-help] Testing FTSP > Hello
Sharmistha,
> In TimeSyncDebugger.nc globaltime = localtime is absolutely correct
> actually.
> If you see next line it looks like
> "d.is_synced = call GlobalTime.local2Global(&d.globalClock);"
>
> here call GlobalTime.local2Global conevrts local clock into
> global clock
> . already stored in (d.globalClock). so after this call
> d.globalClock has
> global clock instead local.
>
> Now lets come to second question. how much time it takes to
> synchronise.Well it depends on -DTIMESYNC_RATE value in your
> make file and
> ENTRY_VALID_LIMIT.
> nodes will be synchronised after interval
> -DTIMESYNC_RATE*ENTRY_VALID_LIMIT.
> for example if you set -DTIMESYNC_RATE=30 and let say
> ENTRY_VALID_LIMIT=4(default).
> then it will take 30*4=120 seconds minimum assuming all
> communication gone
> well.
>
> Hope This helps.
> Regards:
> Santosh Dwivedi
>
>
> On 12/20/05, santosh dwivedi <[EMAIL PROTECTED]> wrote:
> >
> > Hello Sharmistha,
> > In TimeSyncDebugger.nc globaltime = localtime is absolutely correct
> > actually.
> > If you see next line it looks like
> > "d.is_synced = call GlobalTime.local2Global(&d.globalClock);"
> >
> > here call GlobalTime.local2Global conevrts local clock into
> global> clock . already stored in (d.globalClock). so after this call
> > d.globalClock has global clock instead local.
> >
> > Now lets come to second question. how much time it takes to
> synchronise.> Well it depends on -DTIMESYNC_RATE value in your
> make file and
> > ENTRY_VALID_LIMIT.
> > nodes will be synchronised after interval
> > -DTIMESYNC_RATE*ENTRY_VALID_LIMIT.
> > for example if you set -DTIMESYNC_RATE=30 and let say
> > ENTRY_VALID_LIMIT=4(default).
> > then it will take 30*4=120 seconds minimum assuming all
> communication gone
> > well.
> >
> > Hope This helps.
> > Regards:
> > Santosh Dwivedi
> >
> >
> > On 12/20/05, Sharmistha Maitra <[EMAIL PROTECTED]> wrote:
> > >
> > > Hi All,
> > >
> > > This is me again ...
> > >
> > > Yes Santosh, I realised that TimeSyncDebugger.nc makes
> globaltime =
> > > localtime(I do not know why ?); so the real check is
> "is_synched" which in
> > > my case was showing zero, so unsynchronized.
> > >
> > > Does anybody know how long it takes to achieve synch in FTSP ?
> There is
> > > a part in TimeSyncM.nc which says "if timesynch error is
> bigger than the
> > > 100 (ENTRY_THROWOUT_LIMIT) clear the regression table". I
> think this is the
> > > only reason why I am getting zero entries in my table. I have
> kept the
> > > network(a poller, a base station, 2 timesynch nodes) ON for a
> maximum of 2
> > > minutes, do you think I need to wait long to achieve synch ?
> And then
> > > probably I will see values in my regression table ?
> > >
> > > In hardware is there is way to debug (something like
> 'dbg'..this might
> > > be a dumb question..I am sorry) other than the three LEDS on
> the mote ?
> > >
> > > Wish you all a great holidays.....
> > >
> > > Thanks,
> > >
> > > Sharmistha.
> > >
> > >
> > >
> >
>
------------------------------------------------------------------------
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