GNU Radio 4.0 Preliminary Code Review

Prior to bringing newsched into the main gnuradio repository under a dev-4.0 branch, it is necessary to get at least a preliminary review so that the main aspects of the design can be understood and discussed. Let's use this page to document proposed changes to the existing newsched design that need to be done either before or after the mainlining.


 * License
 * GPLv3 - probably don't have much choice here unless we want to have some parts under a different license (e.g. PMTF under lgpl)


 * Git History
 * Very divergent - do we start from scratch and let 3.x and 4.0 each have their own history


 * Build System
 * meson.build - has been tremendously easier than CMake to deal with (some caveats)


 * Code Structure
 * overall arrangement of code
 * subprojects - CLI11, cpp-httplib, cppzmq, json, moodycamel, pmt
 * QA tests


 * Domain specific blocks/buffers - e.g. CUDA
 * Don't have a good solution for making this out of tree but still cohesive (same block with multiple impl)


 * gnuradio-runtime --> gr namespace
 * runtime is now a modular concept so previous gnuradio-runtime just called gr


 * Schedulers
 * Scheduler API
 * CPU Scheduler


 * Message Ports


 * Buffers and Custom Buffers


 * Block API
 * block.h, node.h, port.h


 * Main diffs from GR3
 * No history
 * No forecast
 * Less scheduler "hints"
 * Self contained work function


 * Block Autogen
 * yaml file format
 * jinja templates
 * create_{mod,block} scripts


 * Block Porting
 * what is involved and what can be automated?
 * Options for shimming 4.0 blocks back into 3.x?


 * Kernel Library
 * Separation of kernel namespaces into different library that doesn't depend on blocklib


 * Distributed Operation (concept)
 * Minimal example able to partition and run across instances


 * Documentation
 * Opportunities for cohesive versioned docs
 * Loss of public block header through doxygen


 * Benchmarking
 * What to include in-tree


 * GRC
 * Changes needed to support 4.0 features
 * Plan to move out of tree??
 * Start with QT port or off established GTK GRC?


 * Coding Standard
 * C++ modernization
 * clang-format changes
 * python/pep8 format changes
 * enforce YAML, build system format checks?
 * offer / encourage pre-commit hook usage (e.g. through this)


 * Out-of-Tree / Ecosystem
 * example OOT project
 * modtool (successor? Extension? BW compat?)
 * deb/rpm/conda packaging as default component in OOTs