Add instrumentation, with performance profiling capability (#4132)

* Implement instrumentation for performance profiling

* Add profiling to runtime functions declared in `decl_module` inc.
`on_initialize` and `on_finalize`

* Remove changes

* add docs, tidy up

* fix versions

* fix copyright date

* switch to hashmap and instant

* update example

* update example

* implement receiver for logger and make default

* fix comment

* use `if_std!` macro

* remove whitespace

* fix whitespace

* fix nits

substrate/client/service/src/builder.rs

@@ -35,7 +35,7 @@ use futures03::{
 	StreamExt as _, TryStreamExt as _,
 };
 use keystore::{Store as Keystore};
-use log::{info, warn};
+use log::{info, warn, error};
 use network::{FinalityProofProvider, OnDemand, NetworkService, NetworkStateInfo, DhtEvent};
 use network::{config::BoxFinalityProofRequestBuilder, specialization::NetworkSpecialization};
 use parking_lot::{Mutex, RwLock};
@@ -1130,6 +1130,17 @@ ServiceBuilder<
 			telemetry
 		});
 
+		// Instrumentation
+		if let Some(tracing_targets) = config.tracing_targets.as_ref() {
+			let subscriber = substrate_tracing::ProfilingSubscriber::new(
+				config.tracing_receiver, tracing_targets
+			);
+			match tracing::subscriber::set_global_default(subscriber) {
+				Ok(_) => (),
+				Err(e) => error!(target: "tracing", "Unable to set global default subscriber {}", e),
+			}
+		}
+
 		Ok(Service {
 			client,
 			network,

substrate/client/service/src/config.rs

@@ -98,6 +98,10 @@ pub struct Configuration<C, G, E = NoExtension> {
 	///
 	/// Should only be set when `node` is running development mode.
 	pub dev_key_seed: Option<String>,
+	/// Tracing targets
+	pub tracing_targets: Option<String>,
+	/// Tracing receiver
+	pub tracing_receiver: substrate_tracing::TracingReceiver,
 }
 
 /// Configuration of the database of the client.
@@ -156,6 +160,8 @@ impl<C, G, E> Configuration<C, G, E> where
 			disable_grandpa: false,
 			keystore_password: None,
 			dev_key_seed: None,
+			tracing_targets: Default::default(),
+			tracing_receiver: Default::default(),
 		};
 		configuration.network.boot_nodes = configuration.chain_spec.boot_nodes().to_vec();