[USRP-users] Questions about benchmark_tx/benchmark_rx

Weixian Zhou ideazwx at gmail.com
Fri Jun 1 13:01:36 EDT 2012


I used the benchmark_tx and benchmark_rx to transmit data and I have some
questions:
1. I set the frequency of both benchmark_tx and benchmark_rx to 300M, the
transmission succeed; but it failed when I set the frequency to 2.4G or
other frequencies. Why is this?
2. Both the benchmark_tx and benchmark_rx gives the warning as I marked
red: the actual frequency is not same but the transmission succeed. Why is
it?
3. In the receiving end, the pktno is disordered some pktnos are much
larger than averages. Why is it?
4. What does the n_right=0 means? Does it mean the packet is corrupted in
the receiving end?


*The benchmark_tx messages as following:*
belltestbed at belltestbed-OptiPlex-790
:~/Desktop/gnuradio/gr-digital/les/narrowband$ ./benchmark_tx.py -f 300M
--from-file=pic.jpg
linux; GNU C++ version 4.6.3; Boost_104601; UHD_003.004.002-128-g12f7a5c9

>>> gr_fir_ccf: using SSE
-- Opening a USRP2/N-Series device...
-- Current recv frame size: 1472 bytes
-- Current send frame size: 1472 bytes

UHD Warning:
    The recv buffer could not be resized sufficiently.
    Target sock buff size: 50000000 bytes.
    Actual sock buff size: 1000000 bytes.
    See the transport application notes on buffer resizing.
    Please run: sudo sysctl -w net.core.rmem_max=50000000

UHD Warning:
    The recv buffer could not be resized sufficiently.
    Target sock buff size: 50000000 bytes.
    Actual sock buff size: 1000000 bytes.
    See the transport application notes on buffer resizing.
    Please run: sudo sysctl -w net.core.rmem_max=50000000

UHD Warning:
    The send buffer could not be resized sufficiently.
    Target sock buff size: 1048576 bytes.
    Actual sock buff size: 1000000 bytes.
    See the transport application notes on buffer resizing.
    Please run: sudo sysctl -w net.core.wmem_max=1048576

UHD Warning:
    Unable to set the thread priority. Performance may be negatively
affected.
    Please see the general application notes in the manual for instructions.
    EnvironmentError: OSError: error in pthread_setschedparam

No gain specified.
Setting gain to 17.500000 (from [0.000000, 35.000000])

UHD Warning:
    The hardware does not support the requested TX frequency:
    Target frequency: 300.000000 MHz
    Actual frequency: 4500.000000 MHz

UHD Warning:
    The hardware does not support the requested TX sample rate:
    Target sample rate: 0.050000 MSps
    Actual sample rate: 0.195312 MSps

Symbol Rate:         25000.000000
Requested sps:       2.000000
Given sample rate:   195312.500000
Actual sps for rate: 7.812500

Requested sample rate: 50000.000000
Actual sample rate: 195312.500000
Using Volk machine: avx_32
Warning: failed to enable realtime scheduling
.........................................................................


*And the benchmark_rx messages as follwing:*
bell at bell-HP-Compaq-4000-Pro-SFF-PC
:~/Desktop/USRP/gnuradio/gr-digital/examples/narrowband$ ./benchmark_rx.py
-f 300M
linux; GNU C++ version 4.6.3; Boost_104601; UHD_003.004.001-129-g23344268

>>> gr_fir_ccf: using SSE
-- Opening a USRP2/N-Series device...
-- Current recv frame size: 1472 bytes
-- Current send frame size: 1472 bytes

UHD Warning:
    The recv buffer could not be resized sufficiently.
    Target sock buff size: 50000000 bytes.
    Actual sock buff size: 1000000 bytes.
    See the transport application notes on buffer resizing.
    Please run: sudo sysctl -w net.core.rmem_max=50000000

UHD Warning:
    The recv buffer could not be resized sufficiently.
    Target sock buff size: 50000000 bytes.
    Actual sock buff size: 1000000 bytes.
    See the transport application notes on buffer resizing.
    Please run: sudo sysctl -w net.core.rmem_max=50000000

UHD Warning:
    The send buffer could not be resized sufficiently.
    Target sock buff size: 1048576 bytes.
    Actual sock buff size: 1000000 bytes.
    See the transport application notes on buffer resizing.
    Please run: sudo sysctl -w net.core.wmem_max=1048576

UHD Warning:
    Unable to set the thread priority. Performance may be negatively
affected.
    Please see the general application notes in the manual for instructions.
    EnvironmentError: OSError: error in pthread_setschedparam

No gain specified.
Setting gain to 49.500000 (from [0.000000, 99.000000])

UHD Warning:
    The hardware does not support the requested RX frequency:
    Target frequency: 300.000000 MHz
    Actual frequency: 2400.000000 MHz

UHD Warning:
    The hardware does not support the requested RX sample rate:
    Target sample rate: 0.050000 MSps
    Actual sample rate: 0.195312 MSps

Symbol Rate:         25000.000000
Requested sps:       2.000000
Given sample rate:   195312.500000
Actual sps for rate: 7.812500

Requested sample rate: 50000.000000
Actual sample rate: 195312.500000
Warning: Failed to enable realtime scheduling.
Using Volk machine: ssse3_32
ok = False  pktno = 3850  n_rcvd =    1  n_right =    0
ok = False  pktno = 53042  n_rcvd =    2  n_right =    0
ok = False  pktno = 61454  n_rcvd =    3  n_right =    0
ok = False  pktno =   27  n_rcvd =    4  n_right =    0
ok = False  pktno =   41  n_rcvd =    5  n_right =    0
ok = False  pktno =   44  n_rcvd =    6  n_right =    0
ok = False  pktno =   44  n_rcvd =    7  n_right =    0
ok = False  pktno =   51  n_rcvd =    8  n_right =    0
ok = False  pktno =   43  n_rcvd =    9  n_right =    0
ok = False  pktno =   64  n_rcvd =   10  n_right =    0


I am using two USRP N210.

-- 
Regards,
Weixian Zhou
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