Sorry to reply to myself, but we just got the new Ethernet NIC so both USRP2s report WE_TX flow control. Nothing changed.
And I have a correction for the types of ethernet cards. The onboard NIC is the Broadcom. Ethernet 2 (and now 3) appear to be Realtek RTL8111/8168B. On Sep 3, 2010, at 3:10 PM, Marc Epard wrote: > I'm a puzzled by some UHD behavior and wondering if I need a new host system. > I'm not doing any signal processing in the host -- just transmitting from a > buffer and/or receiving from a buffer. Later, we'll be wanting to do more > processing with two USRP2s both transmitting and receiving at the same time > and may want 25 Msps in some cases. > > I've managed to get simultaneous receive threads going for each of two > USRP2s, both at 25 Msps (big buffers are good). The GUI still updates, but is > a little sluggish. It's fragile, though. If I do much at all with the GUI > (sometimes just moving the mouse), recv's start timing out. System Monitor > shows no memory pressure and both CPUs at 50-60%. FWIW, I'm running my C++ > app via SSH from another machine. > > Transmitting is worse. Even a solo transmit thread at 25 Msps (plus a thread > calling recv_async_msg) causes the GUI to be unusable and I get frequent Us > on both the host and the USRP2's serial port, as well as tons of > EVENT_CODE_SEQ_ERROR and EVENT_CODE_SEQ_ERROR_IN_BURST messages from > recv_async_msg. I can't tell what the CPU utilization is because System > Monitor stops updating. 6.25 Msps is better, but I still get a few Us and a > bunch of EVENT_CODE_SEQ_ERROR and EVENT_CODE_SEQ_ERROR_IN_BURST messages. > System Monitor manages to update and shows CPU utilization of 80% and 55%. > Again, I'm only transmitting from a buffer that I fill once up front and send > over and over again with no signal processing. > > I'm specifying recv_buff_size=100e6 and send_buff_size=100e6; > net.core.rmem_max and net.core.wmem_max are set to 100000000. I'm calling > uhd::set_thread_priority_safe from each of my threads. I'm using the latest > gnuradio and UHD software/firmware/FPGA (the recent release with USRP1 > support). I have Ubuntu 10.4 with stock ethernet drivers. > > I've itemized a few details of the hardware setup below. What systems are you > all using for MIMO-like work with USRP2s and UHD? What systems do you > recommend or wish you had? Are there other changes I should make to my > current system? > > TIA > > -Marc > > Dell DCDO tower manufactured in 2007 > Dual-core Xeon 5110 @ 1.60 GHz > 2 GB RAM > Lots of slots - mix of PCI, PCIe, PCI-X > > Ethernet 0: USRP2 with DBSRX > Onboard 10/100/1000 Ethernet. > USRP2 says no flow control and we're getting another PCI Express card. > > Ethernet 1: network connection > D-Link PCI NIC > No flow control > > Ethernet 2: USRP2 with XCVR2450 > StarTech.com PCI Express 10/100/1000 Ethernet NIC > Ubuntu identifies it as Broadcom NetXtreme BCM5752 > USRP2 says it gets WE_TX flow control > > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
