[Discuss-gnuradio] Tx timestamping w/C++ & "raw" ethernet driver (i.e., non-UHD)

[bobb]

All,

  I'm having a problem getting scheduled transmissions to occur when I *think* 
they should.

  I am sending out tx packets with:

  start_of_burst = 1
  send_now = 0
  end_of_burst = 1 if just 1 packet, else 0
  timestamp = "the appropriate value"

  The timestamp hardware has been configured to reset every PPS.

  The behavior I'm trying to achieve is one/burst packet sent every 640 ms.

  The calculated timestamps appear to be set correctly (i.e., I've checked them 
and they advance by 640ms and wrap when they "overflow" a second).

  I *thought* that the USRP2 might throttle my code (i.e., not accept another 
send (transmit request) while a send is pending) but that does not appear to be 
happening (i.e., the code pretty much continuously sends xmits)

  What I see is a bunch of packets going out, then a few go out, then a bunch 
more (repeat indefinitely).

  I realize a might "buy" myself a little time if I didn't reset the timestamp 
h/w every second, but it will wrap eventually, so I had thought that it didn't 
matter (however, if it does, I'd appreciate learning so).

  Any thoughts/suggestions very much appreciated.

  Thanks!

  --Bob