Rate limit ascending bootstrap requests

nano/node/bootstrap/bootstrap_config.cpp

@@ -36,6 +36,7 @@ nano::error nano::bootstrap_config::deserialize (nano::tomlconfig & toml)
 	toml.get ("enable_dependency_walker", enable_dependency_walker);
 
 	toml.get ("channel_limit", channel_limit);
+	toml.get ("rate_limit", rate_limit);
 	toml.get ("database_rate_limit", database_rate_limit);
 	toml.get ("database_warmup_ratio", database_warmup_ratio);
 	toml.get ("max_pull_count", max_pull_count);
@@ -62,6 +63,7 @@ nano::error nano::bootstrap_config::serialize (nano::tomlconfig & toml) const
 	toml.put ("enable_dependency_walker", enable_dependency_walker, "Enable or disable the 'dependency walker` strategy.\ntype:bool");
 
 	toml.put ("channel_limit", channel_limit, "Maximum number of un-responded requests per channel.\nNote: changing to unlimited (0) is not recommended.\ntype:uint64");
+	toml.put ("rate_limit", rate_limit, "Rate limit on requests.\nNote: changing to unlimited (0) is not recommended as this operation competes for resources with realtime traffic.\ntype:uint64");
 	toml.put ("database_rate_limit", database_rate_limit, "Rate limit on scanning accounts and pending entries from database.\nNote: changing to unlimited (0) is not recommended as this operation competes for resources on querying the database.\ntype:uint64");
 	toml.put ("database_warmup_ratio", database_warmup_ratio, "Ratio of the database rate limit to use for the initial warmup.\ntype:uint64");
 	toml.put ("max_pull_count", max_pull_count, "Maximum number of requested blocks for bootstrap request.\ntype:uint64");

nano/node/bootstrap/bootstrap_config.hpp

@@ -34,7 +34,8 @@ class bootstrap_config final
 
 	// Maximum number of un-responded requests per channel, should be lower or equal to bootstrap server max queue size
 	std::size_t channel_limit{ 16 };
-	std::size_t database_rate_limit{ 256 };
+	std::size_t rate_limit{ 500 };
+	std::size_t database_rate_limit{ 250 };
 	std::size_t database_warmup_ratio{ 10 };
 	std::size_t max_pull_count{ nano::bootstrap_server::max_blocks };
 	std::chrono::milliseconds request_timeout{ 1000 * 5 };

nano/node/bootstrap/bootstrap_service.cpp

@@ -28,6 +28,7 @@ nano::bootstrap_service::bootstrap_service (nano::node_config const & node_confi
 	database_scan{ ledger },
 	throttle{ compute_throttle_size () },
 	scoring{ config, node_config_a.network_params.network },
+	limiter{ config.rate_limit, 1.0 },
 	database_limiter{ config.database_rate_limit, 1.0 }
 {
 	block_processor.batch_processed.add ([this] (auto const & batch) {
@@ -257,7 +258,6 @@ void nano::bootstrap_service::wait (std::function<bool ()> const & predicate) co
 void nano::bootstrap_service::wait_tags () const
 {
 	wait ([this] () {
-		debug_assert (!mutex.try_lock ());
 		return tags.size () < config.max_requests;
 	});
 }
@@ -271,9 +271,14 @@ void nano::bootstrap_service::wait_blockprocessor () const
 
 std::shared_ptr<nano::transport::channel> nano::bootstrap_service::wait_channel ()
 {
+	// Wait until more requests can be sent
+	wait ([this] () {
+		return !limiter.should_pass (1);
+	});
+
+	// Wait until a channel is available
 	std::shared_ptr<nano::transport::channel> channel;
 	wait ([this, &channel] () {
-		debug_assert (!mutex.try_lock ());
 		channel = scoring.channel ();
 		return channel != nullptr; // Wait until a channel is available
 	});

nano/node/bootstrap/bootstrap_service.hpp

@@ -175,6 +175,8 @@ class bootstrap_service
 	// clang-format on
 	ordered_tags tags;
 
+	// Rate limiter for all types of requests
+	nano::rate_limiter limiter;
 	// Requests for accounts from database have much lower hitrate and could introduce strain on the network
 	// A separate (lower) limiter ensures that we always reserve resources for querying accounts from priority queue
 	nano::rate_limiter database_limiter;