Re: [Discuss-gnuradio] Strange uhd::device::send execution times

[Gaetano Mendola]

On Sun, Jun 19, 2011 at 8:44 PM, Gaetano Mendola <address@hidden> wrote:
> I have 12 cores on my server, and I fear the kernel is juggling that thread
> around.

I have solved the issue but still I'm not happy at all with what is going on.

The samples I'm feeding with the USRP N210 are stored on a disk, my sample rate
is 12.5 mega samples per second so in order to maintain that rate for
hours I have
a thread performing I/O from disk and a thread feeding the radio
device. The server
is a dual socket xeon system and when the two threads are scheduled on the same
socket then the uhd::device::send some time lasts too much (some time
even 2 seconds
vs the 0.0036 extimated). To solve the issue I had to perform a cpu
affinity for the
thread inside the UHD library and a cpu affinity for my own thread in
order to have those
two threads on different sockets (core 7 for uhd thread and core 2 for
my own thread).

Unfortunaly there is no way to specify at the time of the device on
which core the thread
has to run, I'll see if I can submit a patch that will permit to build
a device like this:

"address=127.0.0.1,send_buff_size=100e6,lockcore=7"

Regards
Gaetano Mendola


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