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  1. Apr 09, 2024
  3. Apr 08, 2024
    • Léa Narzis's avatar
      Adapt `RemoteExternalities` and its related types to be used with generic hash parameters (#3953) · d733c77e
      Léa Narzis authored 
      Closes  https://github.com/paritytech/polkadot-sdk/issues/3737



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Co-authored-by: command-bot <>
Co-authored-by: default avatarOliver Tale-Yazdi <[email protected]>
Co-authored-by: default avatarBastian Köcher <[email protected]>
      d733c77e
    • Aaro Altonen's avatar
      Integrate litep2p into Polkadot SDK (#2944) · 80616f6d
      Aaro Altonen authored 
      [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.

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Signed-off-by: default avatarAlexandru Vasile <[email protected]>
Co-authored-by: default avatarDmitry Markin <[email protected]>
Co-authored-by: default avatarAlexandru Vasile <[email protected]>
Co-authored-by: default avatarAlexandru Vasile <[email protected]>
      80616f6d