UHD: simple_usrp and resize buffer

GNU Radio
1

Hi all,
Since a few days, i’m trying to use UHD with USRP2/WBX under Windows
Vista
Pro 64 bits. The rx_timed_samples example seems to work but it’s
impossible
to change the recv_buff_size and is really problematic since its default
size is very small (358 samples). Looking at the usrp_simple class it
appears that the recv_buff_size parameter is not taken into account.
Does
somebody know a solution to fix it while continuing to use the
simple_usrp
interface.

Thanks in advance
Damien

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2

RX samples per packet: 358

What your seeing is the print out for the number of samples per packet
(udp datagram). This is independent from the recv_buff_size, which is
the size of the socket buffer.

-Josh

3

Ok. Thank you.
I have another question. I made a simple program to receive samples from
USRP2 with UHD. This program is a slight modification of the
rx_timed_samples example with continuous stream mode and the full buffer
receive mode enabled. My problem is that even with an rx_rate of 1MHz
packets are lost (‘S’ printed in the console). Am i doing something
wrong ?
(i work under Windows vista 64 bit, proc. Core 2 duo 3 Ghz each core,
8GB of
RAM).

Josh B.-2 wrote:

interface.

Thanks in advance
Damien

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4

I have not had a chance to mess with optimization flags for msvc. If
your running cmake from the command line try
cmake -DCMAKE_CXXFLAGS:STRING="/QIfist /arch:SSE2 /G7" …/
or set those flags into CMAKE_CXXFLAGS the the gui during configure

I don’t have experience with msvc optimization flags so I invite you
to experiment and report back :slight_smile: On Monday, I will push up some code
that sets the thread priority to realtime (this helps a bunch with
performance)

-Josh

5

Change the build type in the visual studio IDE from “Debug” to
“Release”. The debug build type disables all optimizations and puts in
debug bloat, while the release build type does the opposite. The
performance difference is massive.

-Josh