Re: [Discuss-gnuradio] UHD host resources and system suggestions

[Marc Epard]

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
> 
> 
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