Re: Distributing a gnuradio-flow diagram across multiple cpu's

[Anish Mangal]

Hi Marcus,

Thanks for the quick reply. Here's a more complete flow diagram that doesn't use the block I mentioned above.

https://pasteboard.co/JvBTisO.png

This uses up most of my CPU, so I was wondering whether it was possible to spread this across multiple distinct computers. I'm sorry, that I can't share my most up to date block diagram which uses actual audio sources instead of coldplay songs, as it is on another machine which I dont have access to at the moment, but this gives a fairly good idea about the number of blocks and processing units.

Thoughts?

On Wed, Oct 14, 2020 at 6:48 PM Marcus Müller <mueller@kit.edu> wrote:

Hi Anish,

what your subject line says, distributing across CPUs, GNU Radio does
automatically.

Across multiple distinct computers, you'll need to add some signal
communications between these computers. The ZeroMQ network sinks and
sources do that for you.

But honestly, the flow graph you show should use nearly no CPU at all.
You should investigate what, in your overall flow graph, not just in the
excerpt you showed, uses up your CPU. This should really not be a big
task for your computer.

Also, you're using an outdated version of GNU Radio. Time to update!

Best regards,
Marcus

On 14/10/2020 15.07, Anish Mangal wrote:
> Hi, This is my very first post to this mailing list, so hello to all. I
> am a beginner in experimenting with gnuradio and sdr (hackrf-one). I am
> working on an application where I want to take multiple audio input
> sources and transmit multiple FM signals over one RF channel via the
> SDR. To this end, I created a basic grc block that looks like this:
>
> https://pasteboard.co/JvBGgj5.png
>
> My plan is to have a top level flow diagram using multiple such blocks
> and sum them to produce a composite FM signal through the hackrf-one.
> With my 4th generation intel i7 CPU, with the hackrf's bandwidth set to
> 6MSPS, I am able to transmit 6 simultaneous fm modulated signals. My
> question is this:
>
> Is it possible to spread this task across multiple computers. If one
> computer could produce the FM modulated signals, and the other computer
> sum them and transmit via the SDR, the number of simultaneous streams
> may be increased.
>
> Another approach might be to offload parts of this block diagram to an
> FPGA processing unit.
>
> My challenge is this. I have no experience of working with an FPGA, and
> limited experience with gnu-radio in general, but I am prepared to put
> in the effort required, however, if someone more experienced than me can
> guide me on the proper approach to go about this, it would be very
> helpful. It may be that I just keep all the processing on ONE powerful
> CPU, and whatever is the max number of simultaneous streams I can get,
> that's it. But if there are cost effective ways of making this design
> more efficient, I'm happy to research and experiment.
>
> 73,
> VU2TVE // Anish
>