[Discuss-gnuradio] Latency control. You asked for it....

[Tom Rondeau]

Some of you at least.

There's been an expressed desire for better control over the latency of a GNU Radio flowgraph. I've just checked in an update to the master (and next) branch that gives you a bit of control over this. Now, when you call tb.start() or tb.run(), these functions take a parameter that specifies the maximum noutput_items a block can ever receive. This means that the most latency you'll see in a block is based off this number.

If you don't change anything in any existing applications, nothing will change as the default is a huge number that no block will ever be asked to process.

For those running graphs with lower latency requirements, it'd be great if you could test this out and report back success or failures.

Also, for running wxGUI applications, you set this value when create the stdgui2.stdapp as the last parameter called man_noutput_items like in the uhd_fft.py app:

    app = stdgui2.stdapp(app_top_block, "UHD FFT", nstatus=1, max_noutput_items=8000)

Tom