From 818c05bbc26777cfa8b6639647bf300051d0e5ec Mon Sep 17 00:00:00 2001
From: Toralf Wittner <tw@dtex.org>
Date: Wed, 12 Feb 2020 11:24:25 +0100
Subject: [PATCH] Add command-line flag to enable yamux flow control. (#4892)
* Add command-line flag to enable yamux flow control.
We never enabled proper flow-control for yamux streams which may cause
stream buffers to exceed their configured limit when the stream
producer outpaces the stream consumer. By switching the window update
mode to on-read, producers will only receive more sending credit when
all data has been consumed from the stream buffer. Using this option
creates backpressure on producers. However depending on the protocol
there is a risk of deadlock, if both endpoints concurrently attempt to
send more data than they have credit for and neither side reads before
finishing their writes. To facilitate proper testing, this PR adds a
command-line flag `use-yamux-flow-control`.
* Replace comment with generic message.
---
substrate/Cargo.lock | 1 +
substrate/client/cli/src/lib.rs | 1 +
substrate/client/cli/src/params.rs | 4 ++++
substrate/client/network/Cargo.toml | 1 +
substrate/client/network/src/config.rs | 3 +++
substrate/client/network/src/service.rs | 10 +++++-----
substrate/client/network/src/transport.rs | 18 +++++++++++++++---
substrate/client/service/test/src/lib.rs | 1 +
substrate/utils/browser/src/lib.rs | 1 +
9 files changed, 32 insertions(+), 8 deletions(-)
diff --git a/substrate/Cargo.lock b/substrate/Cargo.lock
index 0f214fe87aa..8ac3012df7f 100644
--- a/substrate/Cargo.lock
+++ b/substrate/Cargo.lock
@@ -6078,6 +6078,7 @@ dependencies = [
"unsigned-varint",
"void",
"wasm-timer",
+ "yamux",
"zeroize 1.1.0",
]
diff --git a/substrate/client/cli/src/lib.rs b/substrate/client/cli/src/lib.rs
index a2e9fa96dad..7495ad8e756 100644
--- a/substrate/client/cli/src/lib.rs
+++ b/substrate/client/cli/src/lib.rs
@@ -424,6 +424,7 @@ fn fill_network_configuration(
enable_mdns: !is_dev && !cli.no_mdns,
allow_private_ipv4: !cli.no_private_ipv4,
wasm_external_transport: None,
+ use_yamux_flow_control: cli.use_yamux_flow_control
};
config.max_parallel_downloads = cli.max_parallel_downloads;
diff --git a/substrate/client/cli/src/params.rs b/substrate/client/cli/src/params.rs
index 0881247b07d..2ffa8bd61b1 100644
--- a/substrate/client/cli/src/params.rs
+++ b/substrate/client/cli/src/params.rs
@@ -238,6 +238,10 @@ pub struct NetworkConfigurationParams {
#[allow(missing_docs)]
#[structopt(flatten)]
pub node_key_params: NodeKeyParams,
+
+ /// Experimental feature flag.
+ #[structopt(long = "use-yamux-flow-control")]
+ pub use_yamux_flow_control: bool,
}
arg_enum! {
diff --git a/substrate/client/network/Cargo.toml b/substrate/client/network/Cargo.toml
index 10d5f1ce9b6..db3e32393d0 100644
--- a/substrate/client/network/Cargo.toml
+++ b/substrate/client/network/Cargo.toml
@@ -48,6 +48,7 @@ substrate-test-runtime-client = { version = "2.0.0", optional = true, path = "..
unsigned-varint = { version = "0.3.0", features = ["codec"] }
void = "1.0.2"
zeroize = "1.0.0"
+yamux = "0.4.2"
[dev-dependencies]
env_logger = "0.7.0"
diff --git a/substrate/client/network/src/config.rs b/substrate/client/network/src/config.rs
index 6cf2587fe47..87c77fee9f0 100644
--- a/substrate/client/network/src/config.rs
+++ b/substrate/client/network/src/config.rs
@@ -292,6 +292,7 @@ impl Default for NetworkConfiguration {
enable_mdns: false,
allow_private_ipv4: true,
wasm_external_transport: None,
+ use_yamux_flow_control: false,
},
max_parallel_downloads: 5,
}
@@ -348,6 +349,8 @@ pub enum TransportConfig {
/// This parameter exists whatever the target platform is, but it is expected to be set to
/// `Some` only when compiling for WASM.
wasm_external_transport: Option<wasm_ext::ExtTransport>,
+ /// Use flow control for yamux streams if set to true.
+ use_yamux_flow_control: bool,
},
/// Only allow connections within the same process.
diff --git a/substrate/client/network/src/service.rs b/substrate/client/network/src/service.rs
index b4281112f61..3dc8a497649 100644
--- a/substrate/client/network/src/service.rs
+++ b/substrate/client/network/src/service.rs
@@ -235,12 +235,12 @@ impl<B: BlockT + 'static, S: NetworkSpecialization<B>, H: ExHashT> NetworkWorker
u64::from(params.network_config.out_peers) + 15,
));
let (transport, bandwidth) = {
- let (config_mem, config_wasm) = match params.network_config.transport {
- TransportConfig::MemoryOnly => (true, None),
- TransportConfig::Normal { wasm_external_transport, .. } =>
- (false, wasm_external_transport)
+ let (config_mem, config_wasm, flowctrl) = match params.network_config.transport {
+ TransportConfig::MemoryOnly => (true, None, false),
+ TransportConfig::Normal { wasm_external_transport, use_yamux_flow_control, .. } =>
+ (false, wasm_external_transport, use_yamux_flow_control)
};
- transport::build_transport(local_identity, config_mem, config_wasm)
+ transport::build_transport(local_identity, config_mem, config_wasm, flowctrl)
};
let mut builder = SwarmBuilder::new(transport, behaviour, local_peer_id.clone());
if let Some(spawner) = params.executor {
diff --git a/substrate/client/network/src/transport.rs b/substrate/client/network/src/transport.rs
index 6b5c18cf33f..e2c95824f83 100644
--- a/substrate/client/network/src/transport.rs
+++ b/substrate/client/network/src/transport.rs
@@ -17,7 +17,7 @@
use futures::prelude::*;
use libp2p::{
InboundUpgradeExt, OutboundUpgradeExt, PeerId, Transport,
- mplex, identity, yamux, bandwidth, wasm_ext
+ mplex, identity, bandwidth, wasm_ext
};
#[cfg(not(target_os = "unknown"))]
use libp2p::{tcp, dns, websocket, noise};
@@ -36,7 +36,8 @@ pub use self::bandwidth::BandwidthSinks;
pub fn build_transport(
keypair: identity::Keypair,
memory_only: bool,
- wasm_external_transport: Option<wasm_ext::ExtTransport>
+ wasm_external_transport: Option<wasm_ext::ExtTransport>,
+ use_yamux_flow_control: bool
) -> (Boxed<(PeerId, StreamMuxerBox), io::Error>, Arc<bandwidth::BandwidthSinks>) {
// Build configuration objects for encryption mechanisms.
#[cfg(not(target_os = "unknown"))]
@@ -55,7 +56,18 @@ pub fn build_transport(
let mut mplex_config = mplex::MplexConfig::new();
mplex_config.max_buffer_len_behaviour(mplex::MaxBufferBehaviour::Block);
mplex_config.max_buffer_len(usize::MAX);
- let yamux_config = yamux::Config::default();
+
+ let yamux_config = {
+ let mut c = yamux::Config::default();
+ // Only set SYN flag on first data frame sent to the remote.
+ c.set_lazy_open(true);
+ if use_yamux_flow_control {
+ // Enable proper flow-control: window updates are only sent when
+ // buffered data has been consumed.
+ c.set_window_update_mode(yamux::WindowUpdateMode::OnRead);
+ }
+ libp2p::yamux::Config::new(c)
+ };
// Build the base layer of the transport.
let transport = if let Some(t) = wasm_external_transport {
diff --git a/substrate/client/service/test/src/lib.rs b/substrate/client/service/test/src/lib.rs
index 2976e66a298..723c13ec822 100644
--- a/substrate/client/service/test/src/lib.rs
+++ b/substrate/client/service/test/src/lib.rs
@@ -166,6 +166,7 @@ fn node_config<G, E: Clone> (
enable_mdns: false,
allow_private_ipv4: true,
wasm_external_transport: None,
+ use_yamux_flow_control: true,
},
max_parallel_downloads: NetworkConfiguration::default().max_parallel_downloads,
};
diff --git a/substrate/utils/browser/src/lib.rs b/substrate/utils/browser/src/lib.rs
index b054d73ac9a..d82f982e14b 100644
--- a/substrate/utils/browser/src/lib.rs
+++ b/substrate/utils/browser/src/lib.rs
@@ -53,6 +53,7 @@ where
wasm_external_transport: Some(transport.clone()),
allow_private_ipv4: true,
enable_mdns: false,
+ use_yamux_flow_control: true,
};
config.task_executor = Some(Arc::new(move |fut| {
wasm_bindgen_futures::spawn_local(fut)
--
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