On 31 mar 2012, at 15.43, Tom R. wrote:
This has never been a problem with earlier versions of GR/UHD, from about 6
GnuRadio itself does not freeze as a whole (like the grc in the background),
just the running application, which I then need to abort.
this. There isn’t that much difference between the last release
(220.127.116.11) and what you get using the build-gnuradio script. That just
grabs the latest master version from our git repo, and we haven’t done
all that much since the release. That really doesn’t make a lot of
How’s your git? If you’re comfortable doing so, can you check out the
v18.104.22.168 tag on git and try that one instead of the tarball release?
Thanks for your info. My current take on this interrupt issue:
The problem may not be gnuradio or uhd’s “fault”, I now suspect. Instead
somehow the network connection and its settings might cause the
interrupts. However, I am no linux guru so I am learning at the same
time as I am doing.
First, I’ve updated Ubuntu, from release 10.10 to 11.04, but then
nothing worked (just got a completely blank screen without any gui), so
fast-forward upgraded to 11.10 and then both laptops came right back on
track. I then also updated the gnuradio+uhd to latest (3.6.0) version
using the excellent build-gnuradio script (as before), which itself went
just fine (also as before).
Unfortunately, the exact same problem with interrupts (total halt) in
the receiver at high sample rates persists. Note, as before, this
happens (only?) with very high rates over the Ethernet (about 400 mbit/s
or more, the higher rate the sooner it halts, typically just a few secs)
although the computer display no overruns or other errors.
Then by jacking around with the MTU setting (100,500, 1500,5000, etc),
increasing the default too low (and initially also gnuradio complaining)
buffer settings (net.core.rmem_max, net.core.wmem_max), disabling the
Ubuntu network manager (via the menu) and removing the automatic network
configuration when USRPN210 connects and instead setting up the network
connection manually with “sudo ifconfig eth1 192.168.10.1” , I
sometimes can get the Ethernet connection into a state to work with
the N210 at high sampling rates without any interruptions at all !
In that case, a beautiful continuous flow of samples to the crunching
computer (like a fft-plot), at highest possible rate 50 MSPS, 8
bit/samples over the wire. This can happen with a MTU above 1500 (or
more), buffers increased to recommended settings by UHD, and when this
works the Ubuntu system manager tells me that some 834 Mbit/samples
flows through the Ethernet cable, and about 50% load on the CPU-cores,
very nice. Then it also works for repeated runs, not just one “lucky”
one, and for a prolonged period of time (more than an hour). In the
working network state I can also easily provoke nice expected overruns,
strings of ‘ooooooooooo’:hs, which isn’t possible when the Ethernet
connection is in the “wrong” and “interrupted” state - since then it
just halts/stops without further info.
However, finding this working network state is not just a matter of
setting the particular network parameters as I hoped it to be… I
suspect some other things are happening behind the scenes, maybe some
other settings etc (I do not yet have full knowledge of ethernets full
functionality and behavior, there may be more influencing parameters ?)
which prevent me finding the working network state in a consistent
manner. Quite weird.
I have USRP-N210 rev2 (says sticker on the back) but now noticed that
when I burned the latest fw and fpga images with the net burner tool it
prints “Hardware type: n210_r3” although I selected the fpga version
image for rev2 corresponding to my version. Could this be related to my
issue? Haven’t noticed that inconsistent message earlier, though.
If some of this rings any bells, please give me some further advise.
Sorry for long post.