[Discuss-gnuradio] Playing with 3.7

[Marcus D. Leech]

So, I have this flow-graph that mostly works under 3.7 now, except for 
something that's horrible.

In my flow-graph, I have two layers of selectors, to select the input 
for a WX GUI FFT sink.  The layers select either the "raw" or "filtered"
  chunk of bandwidth (coming off the 4 hardware sources), and the other 
layer selects which source.  This worked like a champ in 3.6.5.1--never
  a problem.

Under 3.7.4 (basically, today's master), when I go to select which 
input, there's a significant *pause*, and then the change is applied 
after up to
  about 2 seconds of "hang".   If I go to select the "raw" vs 
"filtered", the whole application freezes solid--the GUI freezes up, no 
displays are updated,
  and the hardware sources start getting massive overruns.

Now, when this thing is running, it consumes about 8% of my system, and 
when it "freezes" it consumes apparently much, much less.

Now, I know that "selectors" are actually kind of a hack that stop the 
flow-graph, reconfigure it, and start it up again.   So, maybe there's
  some kind of deadly-embrace going on.

I can reimplement using adders and multipliers if I have to, but gosh, 
I'd rather not have to.  I'm going to try to reproduce with the
  smallest flowgraph that shows the problem, but a simple quick test 
tonight worked flawlessly.  Sigh.