Yes, that’s a workaround. My point is that this issue is not obvious to 
somebody who isn’t familiar with how the scheduler works.

When using null sources, it makes sense to just use two of them. But what if 
you’re supplying a data stream and need to inject a synchronization sequence in 
the middle, as GSM does? In this case, my workaround is using a Deinterleave 
block to split a burst of data into two branches fed to the first and third 
ports of a Stream Mux, and a Vector Source with the sync sequence fed to the 
second Mux port. This works fine for me.

I still wonder if there’s a way to prevent people from stumbling into the issue 
that’s causing the lock up.

Sean


From: Richard Bell [mailto:richard.be...@gmail.com]
Sent: Thursday, July 09, 2015 3:40 AM
To: Nowlan, Sean
Cc: discuss-gnuradio@gnu.org
Subject: Re: [Discuss-gnuradio] Flowgraph locking up with Stream Mux

I think it's the fact that you are feeding two different ports of the mux by 
one null source that is the issue. The first ports buffer fills before the 
third ports buffer does. When the first is full, it prevents null source from 
creating new outputs, which will cause the graph to stall on the third port 
waiting for items.


Use two distinct null sources and I think it will run fine.

Sent from my iPhone

On Jul 8, 2015, at 7:26 PM, Nowlan, Sean 
<sean.now...@gtri.gatech.edu<mailto:sean.now...@gtri.gatech.edu>> wrote:
I’m somehow getting a simple flowgraph to lock up GNU Radio. It locks up every 
time I run it, after roughly the same amount of time. As you can see in the 
attached image and GRC file, I’m feeding two inputs of a Stream Mux block from 
the same upstream block. Do you imagine why that might cause problems?

I know there are other ways to do what I’ve shown here, but locking up seems 
like a bug.

Thanks,
Sean
<simple_failing_flowgraph.png>
<stream_mux_bug_test.grc>
_______________________________________________
Discuss-gnuradio mailing list
Discuss-gnuradio@gnu.org<mailto:Discuss-gnuradio@gnu.org>
https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
_______________________________________________
Discuss-gnuradio mailing list
Discuss-gnuradio@gnu.org
https://lists.gnu.org/mailman/listinfo/discuss-gnuradio

Reply via email to