[USRP-users] performance issues

Josh Blum josh at joshknows.com
Tue Nov 30 00:42:51 EST 2010

> Let me clarify. I transmit frames between two usrp2+laptop at 25Msamp/s.
> The two USRPs take turns at transmitting. Thus every other frame goes
> into from "A->B" and the others "B->A".  I do it at regular time
> intervals using time stamps where "time_stamp_i = i * time_inverval".
> With the old UHD I was able to use timer_interval=6ms with the new UHD I
> need at least time_interval=100ms. 

There was a bug in the FPGA code where the first packet of a consecutive
timed-burst was dropped and the subsequent packets of that burst sent
ASAP. You may be seeing the effect of the packets being sent properly
because as of the last image, this should not have worked.

Since you are seeing lots of underflow, how early are you sending the
packets to the device? Meaning, how many ms before the timestamp on the



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