Aaro Altonen
80616f6d03
[litep2p](https://github.com/altonen/litep2p) is a libp2p-compatible P2P networking library. It supports all of the features of `rust-libp2p` that are currently being utilized by Polkadot SDK. Compared to `rust-libp2p`, `litep2p` has a quite different architecture which is why the new `litep2p` network backend is only able to use a little of the existing code in `sc-network`. The design has been mainly influenced by how we'd wish to structure our networking-related code in Polkadot SDK: independent higher-levels protocols directly communicating with the network over links that support bidirectional backpressure. A good example would be `NotificationHandle`/`RequestResponseHandle` abstractions which allow, e.g., `SyncingEngine` to directly communicate with peers to announce/request blocks. I've tried running `polkadot --network-backend litep2p` with a few different peer configurations and there is a noticeable reduction in networking CPU usage. For high load (`--out-peers 200`), networking CPU usage goes down from ~110% to ~30% (80 pp) and for normal load (`--out-peers 40`), the usage goes down from ~55% to ~18% (37 pp). These should not be taken as final numbers because: a) there are still some low-hanging optimization fruits, such as enabling [receive window auto-tuning](https://github.com/libp2p/rust-yamux/pull/176), integrating `Peerset` more closely with `litep2p` or improving memory usage of the WebSocket transport b) fixing bugs/instabilities that incorrectly cause `litep2p` to do less work will increase the networking CPU usage c) verification in a more diverse set of tests/conditions is needed Nevertheless, these numbers should give an early estimate for CPU usage of the new networking backend. This PR consists of three separate changes: * introduce a generic `PeerId` (wrapper around `Multihash`) so that we don't have use `NetworkService::PeerId` in every part of the code that uses a `PeerId` * introduce `NetworkBackend` trait, implement it for the libp2p network stack and make Polkadot SDK generic over `NetworkBackend` * implement `NetworkBackend` for litep2p The new library should be considered experimental which is why `rust-libp2p` will remain as the default option for the time being. This PR currently depends on the master branch of `litep2p` but I'll cut a new release for the library once all review comments have been addresses. --------- Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> Co-authored-by: Dmitry Markin <dmitry@markin.tech> Co-authored-by: Alexandru Vasile <60601340+lexnv@users.noreply.github.com> Co-authored-by: Alexandru Vasile <alexandru.vasile@parity.io>
Substrate
Substrate is a next-generation framework for blockchain innovation 🚀.
Getting Started
Head to docs.substrate.io and follow the installation
instructions. Then try out one of the tutorials. Refer to the Docker
instructions to quickly run Substrate, Substrate Node Template, Subkey, or to build a chain spec.
Community & Support
Join the highly active and supportive community on the Substrate Stack Exchange to ask questions about use and problems you run into using this software. Please do report bugs and issues here for anything you suspect requires action in the source.
Contributions & Code of Conduct
Please follow the contributions guidelines as outlined in docs/contributor/CONTRIBUTING.md.
In all communications and contributions, this project follows the Contributor Covenant Code of Conduct.
Security
The security policy and procedures can be found in
docs/contributor/SECURITY.md.
License
- Substrate Primitives (
sp-*), Frame (frame-*) and the pallets (pallets-*), binaries (/bin) and all other utilities are licensed under Apache 2.0. - Substrate Client (/client/*/sc-*) is licensed under GPL v3.0 with a classpath linking exception.
The reason for the split-licensing is to ensure that for the vast majority of teams using Substrate to create feature-chains, then all changes can be made entirely in Apache2-licensed code, allowing teams full freedom over what and how they release and giving licensing clarity to commercial teams.
In the interests of the community, we require any deeper improvements made to Substrate's core logic (e.g. Substrate's internal consensus, crypto or database code) to be contributed back so everyone can benefit.