On Wed, Dec 31, 2008 at 12:32:45PM -0800, Earle Frank wrote: > > Okay I am using the default scheduler. So now I have enabled the logging for > the appropriate thread-per-block scheduler files. > > Here's the heart of my problem. My flow graph has five blocks, A, B, C, D, > E. > Output of A is input to B and C. > Output of C is input to D. > Output of B and D are input to E. > > Block A is a file source. > > Block B has a 1-to-1 input to output function. > > Block C breaks the samples from A into partitions of N samples. The block > does its function over the N samples. Then it outputs the resulting N > values. > > Block D looks at the input and produces an enable signal. The curious > feature, due to implementation, is that this block will only output the > enable signal high once it detects the enable going back low. > > Block E takes the inputs from B and D and only outputs the values of B when > D (the enable) is high.
The bug is that D should always produce an enable output, 1:1 with the input. If you're not sure of the state at start up time, output a reasonable default value. > Running this flow graph hangs. Looking at the log files produced for each > block I see that blocks A & B are BLKD_OUT and blocks C, D & E are BLKD_IN. What's happening is that the buffer between B & E is filling, then between A & B fills, then A blocks and the everything hangs because D isn't outputting the enable/not-enable signal. > In this scenario, an enable signal will exist over a partition boundary, say > starts at N-10 and ends at N+10. > > At the point of hanging: > Block A has produced N values. > Block B has consumed N values and produced N values. > Block C has consumed N values and produced N values. > Block D has consumed N values and produced N-10 values. > Block E has consumed N-10 values. > > If only block A would produce the next N values the system would chug along. > To those smarter than I, is there anything obvious as to why this is > stalling the flow graph? > How does the buffers work in this case? > Block C's input buffer is empty and ready. > Block B has 10 values left in it's output buffer, but shouldn't it be able > to produce more outputs? > > > Thanks again in advance, > EF Eric _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
