Hi Eric, it took me some time to assemble the RS 232 level shifter.
First to explicitly answer your question about realtime scheduling. Yes I did put in the explicit enabling you have told me, and yes, I get no error, i.e. realtime scheduling should be set succesfully. 2010-07-20 20:18, Blossom: > If your machine has any kind of power control and/or frequency > scaling, be sure that it's configured in its "Performance mode". That > is, run at full speed all the time, do not try to save energy, > throttle the CPU, etc. I tried to tune my BIOS settings, but this did not change the behaviour substantly. > > Be sure that flow control is properly configured. > It should look like this with a USRP2 plugged in and powered up: > > $ ethtool -a eth1 > Pause parameters for eth1: > Autonegotiate: on > RX: on > TX: off Yes, this is how it looks on my machine. I also experimentally set it to Autonegotiate: off RX: off TX: off to see, if it would change something, but as you guessed, it did not improve the situation. > On transmit, it'll be a buffer underrun. The host isn't keeping up. I can now confirm that I am seeing bursts of 'UUU...' on the debug port of the USRP2. Some more observations: 1) The 6.31 rt kernel from the ubuntu 10.04 LTS is worse than the default stock 6.32 kernel. 2) Altough the USRP2 is signaling underuns ( I guess this is what U stands for) at the same time I can see in wireshark that I am receiving PAUSE frames. This looks like there might be some buffer size problems. How large are the transmit buffers of the USRP2? 3) I wrote a small test app that blasts out UDP frames on the same interface as fast as it can, and I can see a sustained rate of approx 900Mbits/ses. So I guess it is not a limitation of my hardware. Do you have any other ideas what else I could try? Turning to receive side: I invoked usrp2_fft.py -e eth2 -d 4 and I can see not see 'S' on the terminal. Am I correct in the assumption this means I have no missed packets on receive? Thank you for your help! Roland -- _________________________________________ _ _ | Roland Schwarz OE1RSA |_)(_ | sip:speedsn...@ekiga.net | \__) | mailto:oe1...@oevsv.at ________| http://www.blackspace.at _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
