Yeah, like the head block, it's a copying operation. But that's "relatively cheap". I'm not quite sure about the state of this, but at GRCON '14 work was started on letting blocks define where their buffers are – maybe, one day, as a side effect, we can actually use the same buffers for in- and output and get rid of the copying.
On 12.05.2016 18:07, Richard Bell wrote: > If we wanted that behavior, could we do something similar to what > gating blocks do (like the power squelch), where we pass X number of > items through and after that only consume items without ever producing > anything. Is there an efficiency problem with this technique? > > On Thu, May 12, 2016 at 6:14 AM, Marcus Müller > <marcus.muel...@ettus.com <mailto:marcus.muel...@ettus.com>> wrote: > > Yep, having had a walk over this: if we didn't want to have this > behaviour, we'd need to have some buffer_writer specific > done_policy or so, where we tell the block it should shut down > based on whether all or just any one of its buffer readers > signaled WORK_DONE. > We don't have that, so this is the only way to shut down a graph > tree from a non-source block. > > > On 12.05.2016 14:58, Tom Rondeau wrote: >> On Thu, May 12, 2016 at 5:13 AM, Marcus Müller >> <marcus.muel...@ettus.com <mailto:marcus.muel...@ettus.com>> wrote: >> >> Yeah, I've been actually scratching my head on whether that is >> intentional or not – if we don't have that behaviour, there's >> no chance >> that a leaf in a non-path tree-shaped flow graph can stop the >> flow >> graph, is there? >> >> >> >> Definitely intentional and the way it's worked since the beginning. >> >> Tom >> >> >> >> >> On 12.05.2016 12:23, Sylvain Munaut wrote: >> > Hi, >> > >> > >> >> I thought so, too, at first, but then tested: >> >> >> >> Null src +-> Head --> Null sink0 >> >> \----------> Null sink1 >> >> >> >> >> >> stops. >> >> >> >> I think this is the "am done" message bubbling up from >> head to src, then >> >> src knowing it should be done, then the info "there's no >> input coming >> >> anymore" bubbling down to sink1. Thoughts? >> > I'd classify that as a bug. >> > >> > I don't think that's the intended behavior. (but I tested >> too and >> > that's indeed what happens, even with non-null sink/source) >> > >> > Cheers, >> > >> > Sylvain >> >> >> _______________________________________________ >> 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 <mailto:Discuss-gnuradio@gnu.org> > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > >
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