[USRP-users] b200 Overflows

Marcus D. Leech mleech at ripnet.com
Sat Sep 27 14:48:57 EDT 2014


On 09/27/2014 02:37 PM, Simon Brown via USRP-users wrote:
>
> I do mean fc32, not fc21, being harassed by my dog.
>
> Simon Brown G4ELI
> http://v2.sdr-radio.com
>
You might try one of the UHD test utilities, like benchmark_rate:

linux; GNU C++ version 4.7.2 20121109 (Red Hat 4.7.2-8); Boost_105000; 
UHD_003.007.002-94-ge56809a0

UHD Benchmark Rate Allowed options:
   --help                help message
   --args arg            single uhd device address args
   --duration arg (=10)  duration for the test in seconds
   --rx_rate arg         specify to perform a RX rate test (sps)
   --tx_rate arg         specify to perform a TX rate test (sps)
   --rx_otw arg (=sc16)  specify the over-the-wire sample mode for RX
   --tx_otw arg (=sc16)  specify the over-the-wire sample mode for TX
   --rx_cpu arg (=fc32)  specify the host/cpu sample mode for RX
   --tx_cpu arg (=fc32)  specify the host/cpu sample mode for TX
   --mode arg (=none)    multi-channel sync mode option: none, mimo
   --channels arg (=0)   which channel(s) to use (specify "0", "1", 
"0,1", etc)

     Specify --rx_rate for a receive-only test.
     Specify --tx_rate for a transmit-only test.
     Specify both options for a full-duplex test.


Which will let you know what the very-basic infrastructure "stack" can 
support.


> *From:*USRP-users [mailto:usrp-users-bounces at lists.ettus.com] *On 
> Behalf Of *Simon Brown via USRP-users
> *Sent:* 27 September 2014 19:31
> *To:* usrp-users at lists.ettus.com
> *Subject:* Re: [USRP-users] b200 Overflows
>
> Hi Marcus,
>
> I'll try sc12 tomorrow, possibly later this evening. I'm currently 
> preparing food and adding some diagnostics.
>
> It's probably in the manual, but is there a way to determine the most 
> efficient format for a device without losing resolution, for example 
> sc12 for b200, (maybe) sc16 or fc21 for the N210 etc.? I would like to 
> reduce any network / bus traffic where possible.
>
> Simon Brown G4ELI
> http://v2.sdr-radio.com
>
> *From:*USRP-users [mailto:usrp-users-bounces at lists.ettus.com] *On 
> Behalf Of *Marcus D. Leech via USRP-users
> *Sent:* 27 September 2014 19:11
> *To:* usrp-users at lists.ettus.com <mailto:usrp-users at lists.ettus.com>
> *Subject:* Re: [USRP-users] b200 Overflows
>
> On 09/27/2014 02:00 PM, Simon Brown via USRP-users wrote:
>
> Thanks,
>
> I've tried changing these, still get overruns with sample rates of 
> 8MS/s or higher.
>
> Simon Brown G4ELI
> http://v2.sdr-radio.com
>
> Are you sure that your USB-3.0 interface is actually dealing with the 
> device as a USB-3.0 and not a USB-2.0 device?
>
> If you specify a wire-format of sc8 or sc12, do the overruns go away?  
> This will help distinguish between cases involving CPU exhaustion, and 
> interior
>   bus deficiencies  (I found this on one of my embedded systems--could 
> sustain only 6.4Msps with full-width samples, but was perfectly happy to
>   stream 12.8Msps with 8-bit samples).
>
>
> *From:*USRP-users [mailto:usrp-users-bounces at lists.ettus.com] *On 
> Behalf Of *Marcus D. Leech via USRP-users
> *Sent:* 26 September 2014 20:03
> *To:* usrp-users at lists.ettus.com <mailto:usrp-users at lists.ettus.com>
> *Subject:* Re: [USRP-users] b200 Overflows
>
> On 09/26/2014 02:18 PM, Simon Brown via USRP-users wrote:
>
>     Hi,
>
>     Windows 64-bit: I'm streaming nicely, none of my threads indicate
>     CPU problems (plenty of headroom). At 8MB/s and higher I'm getting
>     fastpath Overrun messages every second or so even though I'm
>     pulling data from the b200 as fast as it's available, I am not CPU
>     limited in any way. Using Intel USB 3.
>
>     FWIW I don't see any way to tune the uhd::rx_streamer -- bigger /
>     more buffers, also I don't see any way to flush either.
>
>     Interestingly if I get my CUDA card working harder (more work on
>     the bus) the Overrun messages appear more frequently. I7 4770k,
>     good motherboard (can't remember what).
>
>     Any suggestions?
>
>     Simon Brown G4ELI
>     http://v2.sdr-radio.com
>
>
>
>
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>
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>
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>
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>
> The USB transport parameters can be tweaked:
>
> http://files.ettus.com/manual/page_transport.html#transport_usb_params
>
>   
>   
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>
>
> -- 
> Marcus Leech
> Principal Investigator
> Shirleys Bay Radio Astronomy Consortium
> http://www.sbrac.org
>
>
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