Make runtime api calls native when possible (#1302)

* Add simple benchmark for the runtime api

* Make the executor support native calls

* Some documentation

* Hide behind `feature = "std"`

* Rework the native calls

* Make all tests compile again

* Make every parameter using the Block serialized/deserialized in the native call

* Forward `UnwindSafe` requirement

* Remove debug stuff

* Add some documentation

* Fixes warnings

* Fixes errors after master rebase

* Fixes compilation after master rebase

* Fixes compilation after rebase

substrate/core/sr-api-macros/benches/bench.rs

@@ -0,0 +1,62 @@
+// Copyright 2018 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate 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.
+
+// Substrate 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 Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
+#[macro_use]
+extern crate criterion;
+extern crate substrate_client;
+extern crate substrate_test_client as test_client;
+extern crate sr_primitives as runtime_primitives;
+
+use criterion::Criterion;
+use test_client::runtime::TestAPI;
+use runtime_primitives::{generic::BlockId, traits::ProvideRuntimeApi};
+
+fn sr_api_benchmark(c: &mut Criterion) {
+	c.bench_function("add one with same runtime api", |b| {
+		let client = test_client::new();
+		let runtime_api = client.runtime_api();
+		let block_id = BlockId::Number(client.info().unwrap().chain.best_number);
+
+		b.iter(|| runtime_api.benchmark_add_one(&block_id, &1))
+	});
+
+	c.bench_function("add one with recreating runtime api", |b| {
+		let client = test_client::new();
+		let block_id = BlockId::Number(client.info().unwrap().chain.best_number);
+
+		b.iter(|| client.runtime_api().benchmark_add_one(&block_id, &1))
+	});
+
+	c.bench_function("vector add one with same runtime api", |b| {
+		let client = test_client::new();
+		let runtime_api = client.runtime_api();
+		let block_id = BlockId::Number(client.info().unwrap().chain.best_number);
+		let data = vec![0; 1000];
+
+		b.iter_with_large_drop(|| runtime_api.benchmark_vector_add_one(&block_id, &data))
+	});
+
+	c.bench_function("vector add one with recreating runtime api", |b| {
+		let client = test_client::new();
+		let block_id = BlockId::Number(client.info().unwrap().chain.best_number);
+		let data = vec![0; 1000];
+
+		b.iter_with_large_drop(|| client.runtime_api().benchmark_vector_add_one(&block_id, &data))
+	});
+}
+
+criterion_group!(benches, sr_api_benchmark);
+criterion_main!(benches);