To avoid the setting in of post-Conference downs: Dearest SDR Community with the Highest count of "Awesome" in the Universe,
discussions at GRCon have made it abundantly clear that PMT needs to be replaced¹. Main issues with PMT are: * broken type system, * low suitability as tool for internal packeted data, * lack of interoperability with anything but the languages we support natively, * platform-dependency of the serialization format, * bugs. (to a far lesser degree: performance.) Having talked to multiple domain experts in networked systems and heterogenous cooperative platforms, I've come to the conclusion, furthermore, that in the interest of RPC'ing everything², the structure of messages exchanged between blocks should be predefined. In this sense, PMT's (limited) ability do describe itself is of no help – instead, it introduces ambiguity. The dominant choice for binary serialization with known schemata is Proto Buffers; however, they require deserialization of a whole message if there's substructures before the field you want to access³. Cap'n Proto[1] (by one of the original authors of protobufs) seems to be a suitable alternative, and comparing it to its competitors, it seems to have achieved a significant level of maturity and has at least one large-scale adopter⁴. Among its advantages seems to be that operations on the message happen in-place (i.e. there's actually a compatible C++ struct representation of the memory layout), which rendered it my favourite library for this job. Now, problem: I've never personally worked with Cap'n Proto, or protobuf, or any modern, non-self-describing serialization library; I've got minimal experience with MessagePack, but as said, that's not probably going to make it due to lack of schema. So, here I am, calling for your experience! Hurl ins(igh|ul)ts at me, preferable here on this list. Best regards, Marcus [1] https://capnproto.org/index.html ¹This doesn't come as a surprise – it's just a good point in time to point this out. ²You've probably noticed that we're working towards a less machine- dependent, more portable, distributable computational model ³This can become problematic for messages with large data blobs in between, or very complex protocol headers ⁴CloudFlare seems to be using Cap'n Proto for Web workers, for example. However, it's but at revision 0.7, which indeed implies a bit of headache – other tools that never reached 1.0 that we rely on include Thrift, and that's really not a club that you'd want to be in. _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
