On 09/07/2014 04:24 PM, Peter Witkowski wrote:
Hello,
I have a simple application written in Python using GNURadio. All I
am trying to accomplish is to have the USRP data be written to disk.
The application works fine when I dump data to /dev/null or run it at
reduced sampling rates. However, when I run at my desired sampling
rate, I have a good amount of buffer overflows (a series of "O"
characters get printed).
The host machine that I am working on should have no problems sampling
at the higher rates, but I have found a curious issue in that not a
whole lot of memory is used up by my GNURadio application.
As a result, I am wondering if there is any way to tell GNURadio to
use larger buffers (on the order of a few GB) in order to prevent data
from being dropped. I noted that there seem to be several function
calls available in the C++ API, but there seems to be a limited set of
these calls in the Python wrappers. Latency is a non-issue for me at
the moment, but I need to capture all the data without dropping a
large amount of data. Note that I have the code running with
"real-time" priorities in Linux.
Thanks for your help. FYI I am running GNURadio on Ubuntu 14.04.
Also, I know that my RAID set-up is capable of writing to disk at
twice the rate of data coming in per benchmarking the HDDs.
--
Peter Witkowski
pwitkow...@gmail.com <mailto:pwitkow...@gmail.com>
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Adding buffering for long-term recording simply delays, by a few
seconds, that point at which your system cannot keep up.
What sample rates are you trying to record? What does your flow-graph
look like?
Buffering is useful to allow you to "ride through" short-term shortfalls
in the ability to handle samples. It is useless for handling the situation
where your long-term ability to keep up falls short of what you
actually need.
Have you tried setting up a ramdisk, and writing to that?
--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org
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