Overrun issue and packet loss

GNU Radio
1

I am facing Overrun issue on 500K sampling rate with USRPN210. I see an
‘O’
after irregular time intervals when I use my flowgrpah . PC is directly
connected to USRP with Ethernet cable. PC details:

Processor: Intel Core i7-2600 CPU @ 3.40GHz 8
Memory: 3.8GiB

GNU C++ version 4.6.3; Boost_104601; UHD_003.005.000-26-gb65a3924
Gnruadio version: 3.6.3rc0

Also to check, I ran ./benchmark_rate --rx_rate 500e3 --duration 300,
three
times and following are the outputs:

Testing receive rate 0.500000 Msps
OO
Benchmark rate summary:
Num received samples: 149997045
Num dropped samples: 726
Num overflows detected: 2

Testing receive rate 0.500000 Msps

Benchmark rate summary:
Num received samples: 149998497
Num dropped samples: 0
Num overflows detected: 0

Testing receive rate 0.500000 Msps
OOO
Benchmark rate summary:
Num received samples: 149997408
Num dropped samples: 1089
Num overflows detected: 3

What could be the issue here? And what can I do to fix this issue as I
am
losing 3 to 4 packets in every 10k packets when I use my flow-graph. Any
comments would be appreciated.

–

Best Regards,

Sam

2

Sam, in linux you have to set something:

I think its this

net.core.rmem_max = 50000000

I tested the script on my box, there is no problem.

-Bob
PS:

[bob@localhost examples]$ ./benchmark_rate --rx_rate 500e3 --duration
30
linux; GNU C++ version 4.4.5 20101112 (Red Hat 4.4.5-2); Boost_104100;
UHD_003.002.001-release

Creating the usrp device with: …
– Opening a USRP2/N-Series device…
– Current recv frame size: 1472 bytes
– Current send frame size: 1472 bytes
Using Device: Single USRP:
Device: USRP2 / N-Series Device
Mboard 0: USRP-N210
RX Channel: 0
RX DSP: 0
RX Dboard: A
RX Subdev: WBX RX + Simple GDB
TX Channel: 0
TX DSP: 0
TX Dboard: A
TX Subdev: WBX TX + Simple GDB

Testing receive rate 0.500000 Msps

Benchmark rate summary:
Num received samples: 15001642
Num dropped samples: 0
Num overflows detected: 0
Num transmitted samples: 0
Num sequence errors: 0
Num underflows detected: 0

Sam mite wrote in post #1118824:

I am facing Overrun issue on 500K sampling rate with USRPN210. I see an
‘O’
after irregular time intervals when I use my flowgrpah . PC is directly
connected to USRP with Ethernet cable. PC details:

Processor: Intel Core i7-2600 CPU @ 3.40GHz 8
Memory: 3.8GiB

GNU C++ version 4.6.3; Boost_104601; UHD_003.005.000-26-gb65a3924
Gnruadio version: 3.6.3rc0

Also to check, I ran ./benchmark_rate --rx_rate 500e3 --duration 300,
three
times and following are the outputs:

Testing receive rate 0.500000 Msps
OO
Benchmark rate summary:
Num received samples: 149997045
Num dropped samples: 726
Num overflows detected: 2

Testing receive rate 0.500000 Msps

Benchmark rate summary:
Num received samples: 149998497
Num dropped samples: 0
Num overflows detected: 0

Testing receive rate 0.500000 Msps
OOO
Benchmark rate summary:
Num received samples: 149997408
Num dropped samples: 1089
Num overflows detected: 3

What could be the issue here? And what can I do to fix this issue as I
am
losing 3 to 4 packets in every 10k packets when I use my flow-graph. Any
comments would be appreciated.

–

Best Regards,

Sam

3

Try running it without anything else on the network or on your computer,
not even X11.

Andrew

4

can somebody please comment on it ? Thanks a head of time.

–
Sam

5

Andrew thanks for your reply.

I open terminal only (on ubuntu12.04 LTS), no other application/window.
Running the command again gave me following output.

Testing receive rate 0.500000 Msps
OOOOO
Benchmark rate summary:
Num received samples: 149995956
Num dropped samples: 1815
Num overflows detected: 5
Num transmitted samples: 0
Num sequence errors: 0
Num underflows detected: 0

Any suggestions? What is the reason for these overruns ?

On Mon, Aug 19, 2013 at 5:08 PM, Andrew D.
[email protected]wrote:

OO
Num overflows detected: 0
am losing 3 to 4 packets in every 10k packets when I use my flow-graph. Any

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–

Best Regards,

Sam