[USRP-users] N210: The total sum of rates exceeds the maximum capacity of the connection.

Marcus D. Leech mleech at ripnet.com
Fri Dec 19 14:40:38 EST 2014


On 12/19/2014 02:35 PM, Anderson, Douglas J. via USRP-users wrote:
> Hi all,
>
> I'm trying to figure out if I may have missed something in setting up 
> the connection between my USRP and laptop.
>
> I'm getting the following error when I try and push the USRP's sample 
> rate past 30MSps:
>
If you want to achieve sample-rates between 25Msps and 50Msps, you'll 
need to use 8-bit wire-format.
   The maximum you can achieve with full-width samples is 25Msps.

Use --wire-format sc8


> $ uhd_fft -s 50M -f 800M
> linux; GNU C++ version 4.8.2; Boost_105400; UHD_003.008.001-42-g8c87a524
> [...]
> UHD Warning:
>     The total sum of rates (50.000000 MSps on 1 channels) exceeds the 
> maximum capacity of the connection.
>     This can cause overflows (O).
>
> Then the flowgraph hangs.
>
> I'm using USRP N210 with SBX on Ubuntu laptop with 82577LM Gigabit 
> Network card.
>
> I have tried connected the USRP directly to the laptop and through a 
> D-Link gigabit switch.
>
> I ran the following commands as recommended on the Latency wiki page:
>
> sudo modprobe -r e1000e
> sudo modprobe e1000e InterruptThrottleRate=0 TxAbsIntDelay=0 
> TxIntDelay=0 RxAbsIntDelay=0 RxIntDelay=0
>
> Here is the other relevant system info:
>
> ------------------------------------------------------
> $ uname -r
> 3.17.0-031700-lowlatency
>
> $ sudo lshw
> [...]
>         *-network
>              description: Ethernet interface
>              product: 82577LM Gigabit Network Connection
>              vendor: Intel Corporation
>              physical id: 19
>              bus info: pci at 0000:00:19.0
>              logical name: eth0
>              version: 05
>              serial: 00:26:b9:d2:92:0a
>              size: 1Gbit/s
>              capacity: 1Gbit/s
>              width: 32 bits
>              clock: 33MHz
>              capabilities: pm msi bus_master cap_list ethernet 
> physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
>              configuration: autonegotiation=on broadcast=yes 
> driver=e1000e driverversion=2.3.2-k duplex=full firmware=0.12-1 
> ip=192.168.130.28 latency=0 link=yes multicast=yes port=twisted pair 
> speed=1Gbit/s
>              resources: irq:25 memory:f6900000-f691ffff 
> memory:f6980000-f6980fff ioport:7040(size=32)
>         *-usb:0
>              description: USB controller
>              product: 5 Series/3400 Series Chipset USB2 Enhanced Host 
> Controller
>              vendor: Intel Corporation
>              physical id: 1a
>              bus info: pci at 0000:00:1a.0
>              version: 05
>              width: 32 bits
>              clock: 33MHz
>              capabilities: pm debug ehci bus_master cap_list
>              configuration: driver=ehci-pci latency=0
>              resources: irq:16 memory:f6970000-f69703ff
> [...]
>
> $ modinfo e1000e |grep version:
> version:        2.3.2-k
>
> $ cat /etc/sysctl.conf |grep max
> net.core.rmem_max=50000000
> net.core.wmem_max=1048576
>
> ------------------------------------------------------
>
> I guess I'm either missing something or not understanding something 
> properly. Any help would be much appreciated!
>
>
> -Doug
>
>
> *Douglas Anderson**| Intern*
> DOC/NTIA/ITS-T | 325 Broadway St., Boulder, CO 80305 | P: 303 497 3582
>
>
> _______________________________________________
> USRP-users mailing list
> USRP-users at lists.ettus.com
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com


-- 
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org

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