Files
pezkuwi-subxt/polkadot/node/network/availability-distribution/src/tests/mod.rs
T
Aaro Altonen 80616f6d03 Integrate litep2p into Polkadot SDK (#2944)
[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>
2024-04-08 16:44:13 +00:00

131 lines
4.0 KiB
Rust

// Copyright (C) Parity Technologies (UK) Ltd.
// This file is part of Polkadot.
// Polkadot is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// Polkadot is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with Polkadot. If not, see <http://www.gnu.org/licenses/>.
use std::collections::HashSet;
use futures::{executor, future, Future};
use polkadot_node_network_protocol::request_response::{IncomingRequest, ReqProtocolNames};
use polkadot_primitives::{Block, CoreState, Hash};
use sp_keystore::KeystorePtr;
use polkadot_node_subsystem_test_helpers as test_helpers;
use super::*;
mod state;
/// State for test harnesses.
use state::{TestHarness, TestState};
/// Mock data useful for testing.
pub(crate) mod mock;
fn test_harness<T: Future<Output = ()>>(
keystore: KeystorePtr,
test_fx: impl FnOnce(TestHarness) -> T,
) {
sp_tracing::try_init_simple();
let pool = sp_core::testing::TaskExecutor::new();
let (context, virtual_overseer) = test_helpers::make_subsystem_context(pool.clone());
let genesis_hash = Hash::repeat_byte(0xff);
let req_protocol_names = ReqProtocolNames::new(&genesis_hash, None);
let (pov_req_receiver, pov_req_cfg) = IncomingRequest::get_config_receiver::<
Block,
sc_network::NetworkWorker<Block, Hash>,
>(&req_protocol_names);
let (chunk_req_receiver, chunk_req_cfg) = IncomingRequest::get_config_receiver::<
Block,
sc_network::NetworkWorker<Block, Hash>,
>(&req_protocol_names);
let subsystem = AvailabilityDistributionSubsystem::new(
keystore,
IncomingRequestReceivers { pov_req_receiver, chunk_req_receiver },
Default::default(),
);
let subsystem = subsystem.run(context);
let test_fut = test_fx(TestHarness { virtual_overseer, pov_req_cfg, chunk_req_cfg, pool });
futures::pin_mut!(test_fut);
futures::pin_mut!(subsystem);
executor::block_on(future::join(test_fut, subsystem)).1.unwrap();
}
/// Simple basic check, whether the subsystem works as expected.
///
/// Exceptional cases are tested as unit tests in `fetch_task`.
#[test]
fn check_basic() {
let state = TestState::default();
test_harness(state.keystore.clone(), move |harness| state.run(harness));
}
/// Check whether requester tries all validators in group.
#[test]
fn check_fetch_tries_all() {
let mut state = TestState::default();
for (_, v) in state.chunks.iter_mut() {
// 4 validators in group, so this should still succeed:
v.push(None);
v.push(None);
v.push(None);
}
test_harness(state.keystore.clone(), move |harness| state.run(harness));
}
/// Check whether requester tries all validators in group
///
/// Check that requester will retry the fetch on error on the next block still pending
/// availability.
#[test]
fn check_fetch_retry() {
let mut state = TestState::default();
state
.cores
.insert(state.relay_chain[2], state.cores.get(&state.relay_chain[1]).unwrap().clone());
// We only care about the first three blocks.
// 1. scheduled
// 2. occupied
// 3. still occupied
state.relay_chain.truncate(3);
// Get rid of unused valid chunks:
let valid_candidate_hashes: HashSet<_> = state
.cores
.get(&state.relay_chain[1])
.iter()
.flat_map(|v| v.iter())
.filter_map(|c| match c {
CoreState::Occupied(core) => Some(core.candidate_hash),
_ => None,
})
.collect();
state.valid_chunks.retain(|(ch, _)| valid_candidate_hashes.contains(ch));
for (_, v) in state.chunks.iter_mut() {
// This should still succeed as cores are still pending availability on next block.
v.push(None);
v.push(None);
v.push(None);
v.push(None);
v.push(None);
}
test_harness(state.keystore.clone(), move |harness| state.run(harness));
}