Bastian, Thanks for the suggestion, it's a good idea but may not meet my requirements (my messages have timestamps, some spaced very closely together, and I'd rather have those loaded up in the queue as soon as possible rather than have to go through a handshaking process).
I ended up moving my file parsing into my sync_block and doing away with the message port since I couldn't figure out a way to have a blocking publish to the queue without modifying GR. This works but in the future I also wanted to distribute that information to other blocks, and with the current approach I'll have to duplicate the file parsing in all of those too. -Michael On Thu, Nov 10, 2016 at 11:07 AM, Bastian Bloessl <[email protected]> wrote: > I don't know a good solution, but when I had a similar problem, I ended up > with: > > - the file parser creates an initial message > - the sync block sends a message back to the file parser when it converted > the message into stream domain > - this message triggers sending the next (actual) message in the parser > block > > Best, > Bastian > > > On 11/10/2016 04:17 PM, Michael Wentz wrote: > >> Nathan, >> >> I don't have any other queue in my block - it's just the one associated >> with the message port. The following starts printing once I send too >> many messages (before the block downstream has started processing them): >> >> WARN ASYNCHRONOUS MESSAGE BUFFER OVERFLOWING; DROPPING MESSAGE >> >> Looking at tpb_thread_body.cc, it seems that maybe I'm in a special case >> given I don't have a handler for the block receiving the messages (it >> decides when to check the queue on its own). In that case it looks like >> the queue is limited to 100 messages? >> >> -Michael >> >> On Wed, Nov 9, 2016 at 6:34 PM, West, Nathan >> <[email protected] <mailto:[email protected]>> wrote: >> >> I'm not sure I understand. There was once a proof of concept >> flowgraph called pmt_smasher that would effectively keep publishing >> messages and the queue grows without bounds which was generally >> considered a low-priority issue (having no back pressure/flow >> control on message ports). >> >> You're describing different behavior than I understand the message >> ports to have. Is the queue that's overflowing some custom queue in >> your block that you dump new messages on to? If so just make that >> queue grow as more messages come in. >> >> Nathan >> >> On Tue, Nov 8, 2016 at 7:27 PM, Michael Wentz <[email protected] >> <mailto:[email protected]>> wrote: >> >> Hi, >> >> I've made a block in Python that has one message port out and no >> other ports. What the block does is simple: read from a file, >> parse data into a dict, convert to a PMT, and publish as a >> message. The port is connected to a sync_block that is acting on >> these messages when it deems fit. My desired behavior is for the >> publisher to fill up the queue as fast as possible and block if >> the queue is full (waiting for room to open up). What I've >> observed is that the queue will instead overflow and messages >> will be dropped. Is there any way to have a blocking call to >> message_port_pub()? >> >> Looking through the code I do see a method in basic_block to get >> the number of messages in the queue, which I could use to decide >> to publish a message or not - but this isn't brought out in the >> SWIG interface. Is there a reason why? If not, I was thinking >> about re-defining the SWIG interface for basic_block in my OOT >> with additional methods, but was wondering if that would create >> conflicts/weird issues. >> >> Any other ideas for how to do this would be appreciated. I >> realize I could parse the file in my sync_block, but that's my >> last resort here. >> >> -Michael >> >> _______________________________________________ >> Discuss-gnuradio mailing list >> [email protected] <mailto:[email protected]> >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> <https://lists.gnu.org/mailman/listinfo/discuss-gnuradio> >> >> >> >> >> >> _______________________________________________ >> Discuss-gnuradio mailing list >> [email protected] >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> >> > -- > Dipl.-Inform. Bastian Bloessl > Distributed Embedded Systems Group > University of Paderborn, Germany > http://www.ccs-labs.org/~bloessl/ >
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