lib.rs

// This file is part of Substrate.

// Copyright (C) 2020-2021 Parity Technologies (UK) Ltd.
// SPDX-License-Identifier: Apache-2.0

// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// 	http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//! Macro for benchmarking a FRAME runtime.

#![cfg_attr(not(feature = "std"), no_std)]

#[cfg(feature = "std")]
mod analysis;
mod tests;
mod utils;

#[cfg(feature = "std")]
pub use analysis::{Analysis, AnalysisChoice, BenchmarkSelector, RegressionModel};
#[doc(hidden)]
pub use frame_support;
#[doc(hidden)]
pub use log;
#[doc(hidden)]
pub use paste;
#[doc(hidden)]
pub use sp_io::storage::root as storage_root;
#[doc(hidden)]
pub use sp_runtime::traits::Zero;
#[doc(hidden)]
pub use sp_std::{self, boxed::Box, prelude::Vec, vec};
#[doc(hidden)]
pub use sp_storage::TrackedStorageKey;
pub use utils::*;

/// Whitelist the given account.
#[macro_export]
macro_rules! whitelist {
	($acc:ident) => {
		frame_benchmarking::benchmarking::add_to_whitelist(
			frame_system::Account::<T>::hashed_key_for(&$acc).into(),
		);
	};
}

/// Construct pallet benchmarks for weighing dispatchables.
///
/// Works around the idea of complexity parameters, named by a single letter (which is usually
/// upper cased in complexity notation but is lower-cased for use in this macro).
///
/// Complexity parameters ("parameters") have a range which is a `u32` pair. Every time a benchmark
/// is prepared and run, this parameter takes a concrete value within the range. There is an
/// associated instancing block, which is a single expression that is evaluated during
/// preparation. It may use `?` (`i.e. `return Err(...)`) to bail with a string error. Here's a
/// few examples:
///
/// ```ignore
/// // These two are equivalent:
/// let x in 0 .. 10;
/// let x in 0 .. 10 => ();
/// // This one calls a setup function and might return an error (which would be terminal).
/// let y in 0 .. 10 => setup(y)?;
/// // This one uses a code block to do lots of stuff:
/// let z in 0 .. 10 => {
///   let a = z * z / 5;
///   let b = do_something(a)?;
///   combine_into(z, b);
/// }
/// ```
///
/// Note that due to parsing restrictions, if the `from` expression is not a single token (i.e. a
/// literal or constant), then it must be parenthesised.
///
/// The macro allows for a number of "arms", each representing an individual benchmark. Using the
/// simple syntax, the associated dispatchable function maps 1:1 with the benchmark and the name of
/// the benchmark is the same as that of the associated function. However, extended syntax allows
/// for arbitrary expresions to be evaluated in a benchmark (including for example,
/// `on_initialize`).
///
/// Note that the ranges are *inclusive* on both sides. This is in contrast to ranges in Rust which
/// are left-inclusive right-exclusive.
///
/// Each arm may also have a block of code which is run prior to any instancing and a block of code
/// which is run afterwards. All code blocks may draw upon the specific value of each parameter
/// at any time. Local variables are shared between the two pre- and post- code blocks, but do not
/// leak from the interior of any instancing expressions.
///
/// Example:
/// ```ignore
/// benchmarks! {
///   where_clause {  where T::A: From<u32> } // Optional line to give additional bound on `T`.
///
///   // first dispatchable: foo; this is a user dispatchable and operates on a `u8` vector of
///   // size `l`
///   foo {
///     let caller = account::<T>(b"caller", 0, benchmarks_seed);
///     let l in 1 .. MAX_LENGTH => initialize_l(l);
///   }: _(Origin::Signed(caller), vec![0u8; l])
///
///   // second dispatchable: bar; this is a root dispatchable and accepts a `u8` vector of size
///   // `l`.
///   // In this case, we explicitly name the call using `bar` instead of `_`.
///   bar {
///     let l in 1 .. MAX_LENGTH => initialize_l(l);
///   }: bar(Origin::Root, vec![0u8; l])
///
///   // third dispatchable: baz; this is a user dispatchable. It isn't dependent on length like the
///   // other two but has its own complexity `c` that needs setting up. It uses `caller` (in the
///   // pre-instancing block) within the code block. This is only allowed in the param instancers
///   // of arms.
///   baz1 {
///     let caller = account::<T>(b"caller", 0, benchmarks_seed);
///     let c = 0 .. 10 => setup_c(&caller, c);
///   }: baz(Origin::Signed(caller))
///
///   // this is a second benchmark of the baz dispatchable with a different setup.
///   baz2 {
///     let caller = account::<T>(b"caller", 0, benchmarks_seed);
///     let c = 0 .. 10 => setup_c_in_some_other_way(&caller, c);
///   }: baz(Origin::Signed(caller))
///
///   // this is benchmarking some code that is not a dispatchable.
///   populate_a_set {
///     let x in 0 .. 10_000;
///     let mut m = Vec::<u32>::new();
///     for i in 0..x {
///       m.insert(i);
///     }
///   }: { m.into_iter().collect::<BTreeSet>() }
/// }
/// ```
///
/// Test functions are automatically generated for each benchmark and are accessible to you when you
/// run `cargo test`. All tests are named `test_benchmark_<benchmark_name>`, expect you to pass them
/// the Runtime Config, and run them in a test externalities environment. The test function runs your
/// benchmark just like a regular benchmark, but only testing at the lowest and highest values for
/// each component. The function will return `Ok(())` if the benchmarks return no errors.
///
/// You can optionally add a `verify` code block at the end of a benchmark to test any final state
/// of your benchmark in a unit test. For example:
///
/// ```ignore
/// sort_vector {
/// 	let x in 1 .. 10000;
/// 	let mut m = Vec::<u32>::new();
/// 	for i in (0..x).rev() {
/// 		m.push(i);
/// 	}
/// }: {
/// 	m.sort();
/// } verify {
/// 	ensure!(m[0] == 0, "You forgot to sort!")
/// }
/// ```
///
/// These `verify` blocks will not affect your benchmark results!
///
/// You can construct benchmark tests like so:
///
/// ```ignore
/// #[test]
/// fn test_benchmarks() {
///   new_test_ext().execute_with(|| {
///     assert_ok!(test_benchmark_dummy::<Test>());
///     assert_err!(test_benchmark_other_name::<Test>(), "Bad origin");
///     assert_ok!(test_benchmark_sort_vector::<Test>());
///     assert_err!(test_benchmark_broken_benchmark::<Test>(), "You forgot to sort!");
///   });
/// }
/// ```
#[macro_export]
macro_rules! benchmarks {
	(
		$( $rest:tt )*
	) => {
		$crate::benchmarks_iter!(
			{ }
			{ }
			( )
			( )
			$( $rest )*
		);
	}
}

/// Same as [`benchmarks`] but for instantiable module.
///
/// NOTE: For pallet declared with [`frame_support::pallet`], use [`benchmarks_instance_pallet`].
#[macro_export]
macro_rules! benchmarks_instance {
	(
		$( $rest:tt )*
	) => {
		$crate::benchmarks_iter!(
			{ I: Instance }
			{ }
			( )
			( )
			$( $rest )*
		);
	}
}

/// Same as [`benchmarks`] but for instantiable pallet declared [`frame_support::pallet`].
///
/// NOTE: For pallet declared with `decl_module!`, use [`benchmarks_instance`].
#[macro_export]
macro_rules! benchmarks_instance_pallet {
	(
		$( $rest:tt )*
	) => {
		$crate::benchmarks_iter!(
			{ I: 'static }
			{ }
			( )
			( )
			$( $rest )*
		);
	}
}

#[macro_export]
#[doc(hidden)]
macro_rules! benchmarks_iter {
	// detect and extract where clause:
	(
		{ $( $instance:ident: $instance_bound:tt )? }
		{ $( $where_clause:tt )* }
		( $( $names:tt )* )
		( $( $names_extra:tt )* )
		where_clause { where $( $where_bound:tt )* }
		$( $rest:tt )*
	) => {
		$crate::benchmarks_iter! {
			{ $( $instance: $instance_bound)? }
			{ $( $where_bound )* }
			( $( $names )* )
			( $( $names_extra )* )
			$( $rest )*
		}
	};
	// detect and extract extra tag:
	(
		{ $( $instance:ident: $instance_bound:tt )? }
		{ $( $where_clause:tt )* }
		( $( $names:tt )* )
		( $( $names_extra:tt )* )
		#[extra]
		$name:ident
		$( $rest:tt )*
	) => {
		$crate::benchmarks_iter! {
			{ $( $instance: $instance_bound )? }
			{ $( $where_clause )* }
			( $( $names )* )
			( $( $names_extra )* $name )
			$name
			$( $rest )*
		}
	};
	// mutation arm:
	(
		{ $( $instance:ident: $instance_bound:tt )? }
		{ $( $where_clause:tt )* }
		( $( $names:tt )* ) // This contains $( $( { $instance } )? $name:ident )*
		( $( $names_extra:tt )* )
		$name:ident { $( $code:tt )* }: _ ( $origin:expr $( , $arg:expr )* )
		verify $postcode:block
		$( $rest:tt )*
	) => {
		$crate::benchmarks_iter! {
			{ $( $instance: $instance_bound )? }
			{ $( $where_clause )* }
			( $( $names )* )
			( $( $names_extra )* )
			$name { $( $code )* }: $name ( $origin $( , $arg )* )
			verify $postcode
			$( $rest )*
		}
	};
	// mutation arm:
	(
		{ $( $instance:ident: $instance_bound:tt )? }
		{ $( $where_clause:tt )* }
		( $( $names:tt )* )
		( $( $names_extra:tt )* )
		$name:ident { $( $code:tt )* }: $dispatch:ident ( $origin:expr $( , $arg:expr )* )
		verify $postcode:block
		$( $rest:tt )*
	) => {
		$crate::benchmarks_iter! {
			{ $( $instance: $instance_bound )? }
			{ $( $where_clause )* }
			( $( $names )* )
			( $( $names_extra )* )
			$name {
				$( $code )*
				let __benchmarked_call_encoded = $crate::frame_support::codec::Encode::encode(
					&<Call<T $(, $instance )?>>::$dispatch($( $arg ),*)
				);
			}: {
				let call_decoded = <
					Call<T $(, $instance )?>
					as $crate::frame_support::codec::Decode
				>::decode(&mut &__benchmarked_call_encoded[..])
					.expect("call is encoded above, encoding must be correct");

				<
					Call<T $(, $instance)? > as $crate::frame_support::traits::UnfilteredDispatchable
				>::dispatch_bypass_filter(call_decoded, $origin.into())?;
			}
			verify $postcode
			$( $rest )*
		}
	};
	// iteration arm:
	(
		{ $( $instance:ident: $instance_bound:tt )? }
		{ $( $where_clause:tt )* }
		( $( $names:tt )* )
		( $( $names_extra:tt )* )
		$name:ident { $( $code:tt )* }: $eval:block
		verify $postcode:block
		$( $rest:tt )*
	) => {
		$crate::benchmark_backend! {
			{ $( $instance: $instance_bound )? }
			$name
			{ $( $where_clause )* }
			{ }
			{ $eval }
			{ $( $code )* }
			$postcode
		}

		#[cfg(test)]
		$crate::impl_benchmark_test!(
			{ $( $where_clause )* }
			{ $( $instance: $instance_bound )? }
			$name
		);

		$crate::benchmarks_iter!(
			{ $( $instance: $instance_bound )? }
			{ $( $where_clause )* }
			( $( $names )* { $( $instance )? } $name )
			( $( $names_extra )* )
			$( $rest )*
		);
	};
	// iteration-exit arm
	(
		{ $( $instance:ident: $instance_bound:tt )? }
		{ $( $where_clause:tt )* }
		( $( $names:tt )* )
		( $( $names_extra:tt )* )
	) => {
		$crate::selected_benchmark!(
			{ $( $where_clause)* }
			{ $( $instance: $instance_bound )? }
			$( $names )*
		);
		$crate::impl_benchmark!(
			{ $( $where_clause )* }
			{ $( $instance: $instance_bound )? }
			( $( $names )* )
			( $( $names_extra ),* )
		);
	};
	// add verify block to _() format
	(
		{ $( $instance:ident: $instance_bound:tt )? }
		{ $( $where_clause:tt )* }
		( $( $names:tt )* )
		( $( $names_extra:tt )* )
		$name:ident { $( $code:tt )* }: _ ( $origin:expr $( , $arg:expr )* )
		$( $rest:tt )*
	) => {
		$crate::benchmarks_iter! {
			{ $( $instance: $instance_bound )? }
			{ $( $where_clause )* }
			( $( $names )* )
			( $( $names_extra )* )
			$name { $( $code )* }: _ ( $origin $( , $arg )* )
			verify { }
			$( $rest )*
		}
	};
	// add verify block to name() format
	(
		{ $( $instance:ident: $instance_bound:tt )? }
		{ $( $where_clause:tt )* }
		( $( $names:tt )* )
		( $( $names_extra:tt )* )
		$name:ident { $( $code:tt )* }: $dispatch:ident ( $origin:expr $( , $arg:expr )* )
		$( $rest:tt )*
	) => {
		$crate::benchmarks_iter! {
			{ $( $instance: $instance_bound )? }
			{ $( $where_clause )* }
			( $( $names )* )
			( $( $names_extra )* )
			$name { $( $code )* }: $dispatch ( $origin $( , $arg )* )
			verify { }
			$( $rest )*
		}
	};
	// add verify block to {} format
	(
		{ $( $instance:ident: $instance_bound:tt )? }
		{ $( $where_clause:tt )* }
		( $( $names:tt )* )
		( $( $names_extra:tt )* )
		$name:ident { $( $code:tt )* }: $eval:block
		$( $rest:tt )*
	) => {
		$crate::benchmarks_iter!(
			{ $( $instance: $instance_bound )? }
			{ $( $where_clause )* }
			( $( $names )* )
			( $( $names_extra )* )
			$name { $( $code )* }: $eval
			verify { }
			$( $rest )*
		);
	};
}

#[macro_export]
#[doc(hidden)]
macro_rules! benchmark_backend {
	// parsing arms
	(
		{ $( $instance:ident: $instance_bound:tt )? }
		$name:ident
		{ $( $where_clause:tt )* }
		{ $( PRE { $( $pre_parsed:tt )* } )* }
		{ $eval:block }
		{
			let $pre_id:tt : $pre_ty:ty = $pre_ex:expr;
			$( $rest:tt )*
		}
		$postcode:block
	) => {
		$crate::benchmark_backend! {
			{ $( $instance: $instance_bound )? }
			$name
			{ $( $where_clause )* }
			{
				$( PRE { $( $pre_parsed )* } )*
				PRE { $pre_id , $pre_ty , $pre_ex }
			}
			{ $eval }
			{ $( $rest )* }
			$postcode
		}
	};
	(
		{ $( $instance:ident: $instance_bound:tt )? }
		$name:ident
		{ $( $where_clause:tt )* }
		{ $( $parsed:tt )* }
		{ $eval:block }
		{
			let $param:ident in ( $param_from:expr ) .. $param_to:expr => $param_instancer:expr;
			$( $rest:tt )*
		}
		$postcode:block
	) => {
		$crate::benchmark_backend! {
			{ $( $instance: $instance_bound )? }
			$name
			{ $( $where_clause )* }
			{
				$( $parsed )*
				PARAM { $param , $param_from , $param_to , $param_instancer }
			}
			{ $eval }
			{ $( $rest )* }
			$postcode
		}
	};
	// mutation arm to look after a single tt for param_from.
	(
		{ $( $instance:ident: $instance_bound:tt )? }
		$name:ident
		{ $( $where_clause:tt )* }
		{ $( $parsed:tt )* }
		{ $eval:block }
		{
			let $param:ident in $param_from:tt .. $param_to:expr => $param_instancer:expr ;
			$( $rest:tt )*
		}
		$postcode:block
	) => {
		$crate::benchmark_backend! {
			{ $( $instance: $instance_bound )? }
			$name
			{ $( $where_clause )* }
			{ $( $parsed )* }
			{ $eval }
			{
				let $param in ( $param_from ) .. $param_to => $param_instancer;
				$( $rest )*
			}
			$postcode
		}
	};
	// mutation arm to look after the default tail of `=> ()`
	(
		{ $( $instance:ident: $instance_bound:tt )? }
		$name:ident
		{ $( $where_clause:tt )* }
		{ $( $parsed:tt )* }
		{ $eval:block }
		{
			let $param:ident in $param_from:tt .. $param_to:expr;
			$( $rest:tt )*
		}
		$postcode:block
	) => {
		$crate::benchmark_backend! {
			{ $( $instance: $instance_bound )? }
			$name
			{ $( $where_clause )* }
			{ $( $parsed )* }
			{ $eval }
			{
				let $param in $param_from .. $param_to => ();
				$( $rest )*
			}
			$postcode
		}
	};
	// mutation arm to look after `let _ =`
	(
		{ $( $instance:ident: $instance_bound:tt )? }
		$name:ident
		{ $( $where_clause:tt )* }
		{ $( $parsed:tt )* }
		{ $eval:block }
		{
			let $pre_id:tt = $pre_ex:expr;
			$( $rest:tt )*
		}
		$postcode:block
	) => {
		$crate::benchmark_backend! {
			{ $( $instance: $instance_bound )? }
			$name
			{ $( $where_clause )* }
			{ $( $parsed )* }
			{ $eval }
			{
				let $pre_id : _ = $pre_ex;
				$( $rest )*
			}
			$postcode
		}
	};
	// actioning arm
	(
		{ $( $instance:ident: $instance_bound:tt )? }
		$name:ident
		{ $( $where_clause:tt )* }
		{
			$( PRE { $pre_id:tt , $pre_ty:ty , $pre_ex:expr } )*
			$( PARAM { $param:ident , $param_from:expr , $param_to:expr , $param_instancer:expr } )*
		}
		{ $eval:block }
		{ $( $post:tt )* }
		$postcode:block
	) => {
		#[allow(non_camel_case_types)]
		struct $name;
		#[allow(unused_variables)]
		impl<T: Config $( <$instance>, $instance: $instance_bound )? >
			$crate::BenchmarkingSetup<T $(, $instance)? > for $name
			where $( $where_clause )*
		{
			fn components(&self) -> $crate::Vec<($crate::BenchmarkParameter, u32, u32)> {
				$crate::vec! [
					$(
						($crate::BenchmarkParameter::$param, $param_from, $param_to)
					),*
				]
			}

			fn instance(
				&self,
				components: &[($crate::BenchmarkParameter, u32)],
				verify: bool
			) -> Result<$crate::Box<dyn FnOnce() -> Result<(), &'static str>>, &'static str> {
				$(
					// Prepare instance
					let $param = components.iter()
						.find(|&c| c.0 == $crate::BenchmarkParameter::$param)
						.ok_or("Could not find component in benchmark preparation.")?
						.1;
				)*
				$(
					let $pre_id : $pre_ty = $pre_ex;
				)*
				$( $param_instancer ; )*
				$( $post )*

				Ok($crate::Box::new(move || -> Result<(), &'static str> {
					$eval;
					if verify {
						$postcode;
					}
					Ok(())
				}))
			}
		}
	};
}

// Creates a `SelectedBenchmark` enum implementing `BenchmarkingSetup`.
//
// Every variant must implement [`BenchmarkingSetup`].
//
// ```nocompile
//
// struct Transfer;
// impl BenchmarkingSetup for Transfer { ... }
//
// struct SetBalance;
// impl BenchmarkingSetup for SetBalance { ... }
//
// selected_benchmark!({} Transfer {} SetBalance);
// ```
#[macro_export]
#[doc(hidden)]
macro_rules! selected_benchmark {
	(
		{ $( $where_clause:tt )* }
		{ $( $instance:ident: $instance_bound:tt )? }
		$( { $( $bench_inst:ident )? } $bench:ident )*
	) => {
		// The list of available benchmarks for this pallet.
		#[allow(non_camel_case_types)]
		enum SelectedBenchmark {
			$( $bench, )*
		}

		// Allow us to select a benchmark from the list of available benchmarks.
		impl<T: Config $( <$instance>, $instance: $instance_bound )? >
			$crate::BenchmarkingSetup<T $(, $instance )? > for SelectedBenchmark
			where $( $where_clause )*
		{
			fn components(&self) -> $crate::Vec<($crate::BenchmarkParameter, u32, u32)> {
				match self {
					$(
						Self::$bench => <
							$bench as $crate::BenchmarkingSetup<T $(, $bench_inst)? >
						>::components(&$bench),
					)*
				}
			}

			fn instance(
				&self,
				components: &[($crate::BenchmarkParameter, u32)],
				verify: bool
			) -> Result<$crate::Box<dyn FnOnce() -> Result<(), &'static str>>, &'static str> {
				match self {
					$(
						Self::$bench => <
							$bench as $crate::BenchmarkingSetup<T $(, $bench_inst)? >
						>::instance(&$bench, components, verify),
					)*
				}
			}
		}
	};
}

#[macro_export]
#[doc(hidden)]
macro_rules! impl_benchmark {
	(
		{ $( $where_clause:tt )* }
		{ $( $instance:ident: $instance_bound:tt )? }
		( $( { $( $name_inst:ident )? } $name:ident )* )
		( $( $name_extra:ident ),* )
	) => {
		impl<T: Config $(<$instance>, $instance: $instance_bound )? >
			$crate::Benchmarking<$crate::BenchmarkResults> for Pallet<T $(, $instance)? >
			where T: frame_system::Config, $( $where_clause )*
		{
			fn benchmarks(extra: bool) -> $crate::Vec<&'static [u8]> {
				let mut all = $crate::vec![ $( stringify!($name).as_ref() ),* ];
				if !extra {
					let extra = [ $( stringify!($name_extra).as_ref() ),* ];
					all.retain(|x| !extra.contains(x));
				}
				all
			}

			fn run_benchmark(
				extrinsic: &[u8],
				lowest_range_values: &[u32],
				highest_range_values: &[u32],
				steps: (u32, u32),
				repeat: (u32, u32),
				whitelist: &[$crate::TrackedStorageKey],
				verify: bool,
			) -> Result<$crate::Vec<$crate::BenchmarkResults>, &'static str> {
				// Map the input to the selected benchmark.
				let extrinsic = $crate::sp_std::str::from_utf8(extrinsic)
					.map_err(|_| "`extrinsic` is not a valid utf8 string!")?;
				let selected_benchmark = match extrinsic {
					$( stringify!($name) => SelectedBenchmark::$name, )*
					_ => return Err("Could not find extrinsic."),
				};
				let mut results: $crate::Vec<$crate::BenchmarkResults> = $crate::Vec::new();

				// Add whitelist to DB including whitelisted caller
				let mut whitelist = whitelist.to_vec();
				let whitelisted_caller_key =
					<frame_system::Account::<T> as $crate::frame_support::storage::StorageMap<_,_>>::hashed_key_for(
						$crate::whitelisted_caller::<T::AccountId>()
					);
				whitelist.push(whitelisted_caller_key.into());
				$crate::benchmarking::set_whitelist(whitelist);

				// Warm up the DB
				$crate::benchmarking::commit_db();
				$crate::benchmarking::wipe_db();

				let components = <
					SelectedBenchmark as $crate::BenchmarkingSetup<T $(, $instance)?>
				>::components(&selected_benchmark);

				let mut progress = $crate::benchmarking::current_time();

				let mut do_benchmark = |
					c: &[($crate::BenchmarkParameter, u32)],
					results: &mut $crate::Vec<$crate::BenchmarkResults>,
					verify: bool,
				| -> Result<(), &'static str> {
					// Set up the externalities environment for the setup we want to
					// benchmark.
					let closure_to_benchmark = <
						SelectedBenchmark as $crate::BenchmarkingSetup<T $(, $instance)?>
					>::instance(&selected_benchmark, c, verify)?;

					// Set the block number to at least 1 so events are deposited.
					if $crate::Zero::is_zero(&frame_system::Pallet::<T>::block_number()) {
						frame_system::Pallet::<T>::set_block_number(1u32.into());
					}

					// Commit the externalities to the database, flushing the DB cache.
					// This will enable worst case scenario for reading from the database.
					$crate::benchmarking::commit_db();

					// Reset the read/write counter so we don't count operations in the setup process.
					$crate::benchmarking::reset_read_write_count();

					if verify {
						closure_to_benchmark()?;
					} else {
						// Time the extrinsic logic.
						$crate::log::trace!(
							target: "benchmark",
							"Start Benchmark: {:?}", c
						);

						let start_pov = $crate::benchmarking::proof_size();
						let start_extrinsic = $crate::benchmarking::current_time();

						closure_to_benchmark()?;

						let finish_extrinsic = $crate::benchmarking::current_time();
						let end_pov = $crate::benchmarking::proof_size();

						// Calculate the diff caused by the benchmark.
						let elapsed_extrinsic = finish_extrinsic.saturating_sub(start_extrinsic);
						let diff_pov = match (start_pov, end_pov) {
							(Some(start), Some(end)) => end.saturating_sub(start),
							_ => Default::default(),
						};

						// Commit the changes to get proper write count
						$crate::benchmarking::commit_db();
						$crate::log::trace!(
							target: "benchmark",
							"End Benchmark: {} ns", elapsed_extrinsic
						);
						let read_write_count = $crate::benchmarking::read_write_count();
						$crate::log::trace!(
							target: "benchmark",
							"Read/Write Count {:?}", read_write_count
						);

						// Time the storage root recalculation.
						let start_storage_root = $crate::benchmarking::current_time();
						$crate::storage_root();
						let finish_storage_root = $crate::benchmarking::current_time();
						let elapsed_storage_root = finish_storage_root - start_storage_root;

						let read_and_written_keys = $crate::benchmarking::get_read_and_written_keys();

						results.push($crate::BenchmarkResults {
							components: c.to_vec(),
							extrinsic_time: elapsed_extrinsic,
							storage_root_time: elapsed_storage_root,
							reads: read_write_count.0,
							repeat_reads: read_write_count.1,
							writes: read_write_count.2,
							repeat_writes: read_write_count.3,
							proof_size: diff_pov,
							keys: read_and_written_keys,
						});
					}

					// Wipe the DB back to the genesis state.
					$crate::benchmarking::wipe_db();

					Ok(())
				};

				let (current_step, total_steps) = steps;

				if components.is_empty() {
					// The CLI could ask to do more steps than is sensible, so we skip those.
					if current_step == 0 {
						if verify {
							// If `--verify` is used, run the benchmark once to verify it would complete.
							do_benchmark(Default::default(), &mut $crate::Vec::new(), true)?;
						}
						do_benchmark(Default::default(), &mut results, false)?;
					}
				} else {
					// Select the component we will be benchmarking. Each component will be benchmarked.
					for (idx, (name, low, high)) in components.iter().enumerate() {

						let lowest = lowest_range_values.get(idx).cloned().unwrap_or(*low);
						let highest = highest_range_values.get(idx).cloned().unwrap_or(*high);

						let diff = highest - lowest;

						// Create up to `STEPS` steps for that component between high and low.
						let step_size = (diff / total_steps).max(1);
						let num_of_steps = diff / step_size + 1;

						// The CLI could ask to do more steps than is sensible, so we just skip those.
						if current_step >= num_of_steps {
							continue;
						}

						// This is the value we will be testing for component `name`
						let component_value = lowest + step_size * current_step;

						// Select the max value for all the other components.
						let c: $crate::Vec<($crate::BenchmarkParameter, u32)> = components.iter()
							.enumerate()
							.map(|(idx, (n, _, h))|
								if n == name {
									(*n, component_value)
								} else {
									(*n, *highest_range_values.get(idx).unwrap_or(h))
								}
							)
							.collect();

						if verify {
							// If `--verify` is used, run the benchmark once to verify it would complete.
							do_benchmark(&c, &mut $crate::Vec::new(), true)?;
						}
						do_benchmark(&c, &mut results, false)?;
					}
				}
				return Ok(results);
			}
		}

		/// Test a particular benchmark by name.
		///
		/// This isn't called `test_benchmark_by_name` just in case some end-user eventually
		/// writes a benchmark, itself called `by_name`; the function would be shadowed in
		/// that case.
		///
		/// This is generally intended to be used by child test modules such as those created
		/// by the `impl_benchmark_test_suite` macro. However, it is not an error if a pallet
		/// author chooses not to implement benchmarks.
		#[cfg(test)]
		#[allow(unused)]
		fn test_bench_by_name<T>(name: &[u8]) -> Result<(), &'static str>
		where
			T: Config + frame_system::Config, $( $where_clause )*
		{
			let name = $crate::sp_std::str::from_utf8(name)
				.map_err(|_| "`name` is not a valid utf8 string!")?;
			match name {
				$( stringify!($name) => {
					$crate::paste::paste! { [< test_benchmark_ $name >]::<T>() }
				} )*
				_ => Err("Could not find test for requested benchmark."),
			}
		}
	};
}

// This creates a unit test for one benchmark of the main benchmark macro.
// It runs the benchmark using the `high` and `low` value for each component
// and ensure that everything completes successfully.
#[macro_export]
#[doc(hidden)]
macro_rules! impl_benchmark_test {
	(
		{ $( $where_clause:tt )* }
		{ $( $instance:ident: $instance_bound:tt )? }
		$name:ident
	) => {
		$crate::paste::item! {
			fn [<test_benchmark_ $name>] <T: Config > () -> Result<(), &'static str>
				where T: frame_system::Config, $( $where_clause )*
			{
				let selected_benchmark = SelectedBenchmark::$name;
				let components = <
					SelectedBenchmark as $crate::BenchmarkingSetup<T, _>
				>::components(&selected_benchmark);

				let execute_benchmark = |
					c: $crate::Vec<($crate::BenchmarkParameter, u32)>
				| -> Result<(), &'static str> {
					// Set up the benchmark, return execution + verification function.
					let closure_to_verify = <
						SelectedBenchmark as $crate::BenchmarkingSetup<T, _>
					>::instance(&selected_benchmark, &c, true)?;

					// Set the block number to at least 1 so events are deposited.
					if $crate::Zero::is_zero(&frame_system::Pallet::<T>::block_number()) {
						frame_system::Pallet::<T>::set_block_number(1u32.into());
					}

					// Run execution + verification
					closure_to_verify()?;

					// Reset the state
					$crate::benchmarking::wipe_db();

					Ok(())
				};

				if components.is_empty() {
					execute_benchmark(Default::default())?;
				} else {
					for (_, (name, low, high)) in components.iter().enumerate() {
						// Test only the low and high value, assuming values in the middle won't break
						for component_value in $crate::vec![low, high] {
							// Select the max value for all the other components.
							let c: $crate::Vec<($crate::BenchmarkParameter, u32)> = components.iter()
								.enumerate()
								.map(|(_, (n, _, h))|
									if n == name {
										(*n, *component_value)
									} else {
										(*n, *h)
									}
								)
								.collect();

							execute_benchmark(c)?;
						}
					}
				}
				Ok(())
			}
		}
	};
}

/// This creates a test suite which runs the module's benchmarks.
///
/// When called in `pallet_example` as
///
/// ```rust,ignore
/// impl_benchmark_test_suite!(Pallet, crate::tests::new_test_ext(), crate::tests::Test);
/// ```
///
/// It expands to the equivalent of:
///
/// ```rust,ignore
/// #[cfg(test)]
/// mod tests {
/// 	use super::*;
/// 	use crate::tests::{new_test_ext, Test};
/// 	use frame_support::assert_ok;
///
/// 	#[test]
/// 	fn test_benchmarks() {
/// 		new_test_ext().execute_with(|| {
/// 			assert_ok!(test_benchmark_accumulate_dummy::<Test>());
/// 			assert_ok!(test_benchmark_set_dummy::<Test>());
/// 			assert_ok!(test_benchmark_another_set_dummy::<Test>());
/// 			assert_ok!(test_benchmark_sort_vector::<Test>());
/// 		});
/// 	}
/// }
/// ```
///
/// ## Arguments
///
/// The first argument, `module`, must be the path to this crate's module.
///
/// The second argument, `new_test_ext`, must be a function call which returns either a
/// `sp_io::TestExternalities`, or some other type with a similar interface.
///
/// Note that this function call is _not_ evaluated at compile time, but is instead copied textually
/// into each appropriate invocation site.
///
/// The third argument, `test`, must be the path to the runtime. The item to which this must refer
/// will generally take the form:
///
/// ```rust,ignore
/// frame_support::construct_runtime!(
/// 	pub enum Test where ...
/// 	{ ... }
/// );
/// ```
///
/// There is an optional fourth argument, with keyword syntax: `benchmarks_path = path_to_benchmarks_invocation`.
/// In the typical case in which this macro is in the same module as the `benchmarks!` invocation,
/// you don't need to supply this. However, if the `impl_benchmark_test_suite!` invocation is in a
/// different module than the `benchmarks!` invocation, then you should provide the path to the
/// module containing the `benchmarks!` invocation:
///
/// ```rust,ignore
/// mod benches {
/// 	benchmarks!{
/// 		...
/// 	}
/// }
///
/// mod tests {
/// 	// because of macro syntax limitations, neither Pallet nor benches can be paths, but both have
/// 	// to be idents in the scope of `impl_benchmark_test_suite`.
/// 	use crate::{benches, Pallet};
///
/// 	impl_benchmark_test_suite!(Pallet, new_test_ext(), Test, benchmarks_path = benches);
///
/// 	// new_test_ext and the Test item are defined later in this module
/// }
/// ```
///
/// There is an optional fifth argument, with keyword syntax: `extra = true` or `extra = false`.
/// By default, this generates a test suite which iterates over all benchmarks, including those
/// marked with the `#[extra]` annotation. Setting `extra = false` excludes those.
///
/// There is an optional sixth argument, with keyword syntax: `exec_name = custom_exec_name`.
/// By default, this macro uses `execute_with` for this parameter. This argument, if set, is subject
/// to these restrictions:
///
/// - It must be the name of a method applied to the output of the `new_test_ext` argument.
/// - That method must have a signature capable of receiving a single argument of the form `impl FnOnce()`.
// ## Notes (not for rustdoc)
//
// The biggest challenge for this macro is communicating the actual test functions to be run. We
// can't just build an array of function pointers to each test function and iterate over it, because
// the test functions are parameterized by the `Test` type. That's incompatible with
// monomorphization: if it were legal, then even if the compiler detected and monomorphized the
// functions into only the types of the callers, which implementation would the function pointer
// point to? There would need to be some kind of syntax for selecting the destination of the pointer
// according to a generic argument, and in general it would be a huge mess and not worth it.
//
// Instead, we're going to steal a trick from `fn run_benchmark`: generate a function which is
// itself parametrized by `Test`, which accepts a `&[u8]` parameter containing the name of the
// benchmark, and dispatches based on that to the appropriate real test implementation. Then, we can
// just iterate over the `Benchmarking::benchmarks` list to run the actual implementations.
#[macro_export]
macro_rules! impl_benchmark_test_suite {
	// user might or might not have set some keyword arguments; set the defaults
	//
	// The weird syntax indicates that `rest` comes only after a comma, which is otherwise optional
	(
		$bench_module:ident,
		$new_test_ext:expr,
		$test:path
		$(, $( $rest:tt )* )?
	) => {
		impl_benchmark_test_suite!(
			@selected:
				$bench_module,
				$new_test_ext,
				$test,
				benchmarks_path = super,
				extra = true,
				exec_name = execute_with,
			@user:
				$( $( $rest )* )?
		);
	};
	// pick off the benchmarks_path keyword argument
	(
		@selected:
			$bench_module:ident,
			$new_test_ext:expr,
			$test:path,
			benchmarks_path = $old:ident,
			extra = $extra:expr,
			exec_name = $exec_name:ident,
		@user:
			benchmarks_path = $benchmarks_path:ident
			$(, $( $rest:tt )* )?
	) => {
		impl_benchmark_test_suite!(
			@selected:
				$bench_module,
				$new_test_ext,
				$test,
				benchmarks_path = $benchmarks_path,
				extra = $extra,
				exec_name = $exec_name,
			@user:
				$( $( $rest )* )?
		);
	};
	// pick off the extra keyword argument
	(
		@selected:
			$bench_module:ident,
			$new_test_ext:expr,
			$test:path,
			benchmarks_path = $benchmarks_path:ident,
			extra = $old:expr,
			exec_name = $exec_name:ident,
		@user:
			extra = $extra:expr
			$(, $( $rest:tt )* )?
	) => {
		impl_benchmark_test_suite!(
			@selected:
				$bench_module,
				$new_test_ext,
				$test,
				benchmarks_path = $benchmarks_path,
				extra = $extra,
				exec_name = $exec_name,
			@user:
				$( $( $rest )* )?
		);
	};
	// pick off the exec_name keyword argument
	(
		@selected:
			$bench_module:ident,
			$new_test_ext:expr,
			$test:path,
			benchmarks_path = $benchmarks_path:ident,
			extra = $extra:expr,
			exec_name = $old:ident,
		@user:
			exec_name = $exec_name:ident
			$(, $( $rest:tt )* )?
	) => {
		impl_benchmark_test_suite!(
			@selected:
				$bench_module,
				$new_test_ext,
				$test,
				benchmarks_path = $benchmarks_path,
				extra = $extra,
				exec_name = $exec_name,
			@user:
				$( $( $rest )* )?
		);
	};
	// all options set; nothing else in user-provided keyword arguments
	(
		@selected:
			$bench_module:ident,
			$new_test_ext:expr,
			$test:path,
			benchmarks_path = $path_to_benchmarks_invocation:ident,
			extra = $extra:expr,
			exec_name = $exec_name:ident,
		@user:
			$(,)?
	) => {
		#[cfg(test)]
		mod benchmark_tests {
			use $path_to_benchmarks_invocation::test_bench_by_name;
			use super::$bench_module;

			#[test]
			fn test_benchmarks() {
				$new_test_ext.$exec_name(|| {
					use $crate::Benchmarking;

					let mut anything_failed = false;
					println!("failing benchmark tests:");
					for benchmark_name in $bench_module::<$test>::benchmarks($extra) {
						match std::panic::catch_unwind(|| test_bench_by_name::<$test>(benchmark_name)) {
							Err(err) => {
								println!("{}: {:?}", String::from_utf8_lossy(benchmark_name), err);
								anything_failed = true;
							},
							Ok(Err(err)) => {
								println!("{}: {}", String::from_utf8_lossy(benchmark_name), err);
								anything_failed = true;
							},
							Ok(Ok(_)) => (),
						}
					}
					assert!(!anything_failed);
				});
			}
		}
	};
}

/// show error message and debugging info for the case of an error happening
/// during a benchmark
pub fn show_benchmark_debug_info(
	instance_string: &[u8],
	benchmark: &[u8],
	lowest_range_values: &sp_std::prelude::Vec<u32>,
	highest_range_values: &sp_std::prelude::Vec<u32>,
	steps: &(u32, u32),
	repeat: &(u32, u32),
	verify: &bool,
	error_message: &str,
) -> sp_runtime::RuntimeString {
	sp_runtime::format_runtime_string!(
		"\n* Pallet: {}\n\
		* Benchmark: {}\n\
		* Lowest_range_values: {:?}\n\
		* Highest_range_values: {:?}\n\
		* Steps: {:?}\n\
		* Repeat: {:?}\n\
		* Verify: {:?}\n\
		* Error message: {}",
		sp_std::str::from_utf8(instance_string)
			.expect("it's all just strings ran through the wasm interface. qed"),
		sp_std::str::from_utf8(benchmark)
			.expect("it's all just strings ran through the wasm interface. qed"),
		lowest_range_values,
		highest_range_values,
		steps.1,
		repeat.1,
		verify,
		error_message,
	)
}

/// This macro adds pallet benchmarks to a `Vec<BenchmarkBatch>` object.
///
/// First create an object that holds in the input parameters for the benchmark:
///
/// ```ignore
/// let params = (&config, &whitelist);
/// ```
///
/// The `whitelist` is a parameter you pass to control the DB read/write tracking.
/// We use a vector of [TrackedStorageKey](./struct.TrackedStorageKey.html), which is a simple struct used to set
/// if a key has been read or written to.
///
/// For values that should be skipped entirely, we can just pass `key.into()`. For example:
///
/// ```
/// use frame_benchmarking::TrackedStorageKey;
/// let whitelist: Vec<TrackedStorageKey> = vec![
/// 	// Block Number
/// 	hex_literal::hex!("26aa394eea5630e07c48ae0c9558cef702a5c1b19ab7a04f536c519aca4983ac").to_vec().into(),
/// 	// Total Issuance
/// 	hex_literal::hex!("c2261276cc9d1f8598ea4b6a74b15c2f57c875e4cff74148e4628f264b974c80").to_vec().into(),
/// 	// Execution Phase
/// 	hex_literal::hex!("26aa394eea5630e07c48ae0c9558cef7ff553b5a9862a516939d82b3d3d8661a").to_vec().into(),
/// 	// Event Count
/// 	hex_literal::hex!("26aa394eea5630e07c48ae0c9558cef70a98fdbe9ce6c55837576c60c7af3850").to_vec().into(),
/// ];
/// ```
///
/// Then define a mutable local variable to hold your `BenchmarkBatch` object:
///
/// ```ignore
/// let mut batches = Vec::<BenchmarkBatch>::new();
/// ````
///
/// Then add the pallets you want to benchmark to this object, using their crate name and generated
/// module struct:
///
/// ```ignore
/// add_benchmark!(params, batches, pallet_balances, Balances);
/// add_benchmark!(params, batches, pallet_session, SessionBench::<Runtime>);
/// add_benchmark!(params, batches, frame_system, SystemBench::<Runtime>);
/// ...
/// ```
///
/// At the end of `dispatch_benchmark`, you should return this batches object.
///
/// In the case where you have multiple instances of a pallet that you need to separately benchmark,
/// the name of your module struct will be used as a suffix to your outputted weight file. For
/// example:
///
/// ```ignore
/// add_benchmark!(params, batches, pallet_balances, Balances); // pallet_balances.rs
/// add_benchmark!(params, batches, pallet_collective, Council); // pallet_collective_council.rs
/// add_benchmark!(params, batches, pallet_collective, TechnicalCommittee); // pallet_collective_technical_committee.rs
/// ```
///
/// You can manipulate this suffixed string by using a type alias if needed. For example:
///
/// ```ignore
/// type Council2 = TechnicalCommittee;
/// add_benchmark!(params, batches, pallet_collective, Council2); // pallet_collective_council_2.rs
/// ```

#[macro_export]
macro_rules! add_benchmark {
	( $params:ident, $batches:ident, $name:path, $( $location:tt )* ) => (
		let name_string = stringify!($name).as_bytes();
		let instance_string = stringify!( $( $location )* ).as_bytes();
		let (config, whitelist) = $params;
		let $crate::BenchmarkConfig {
			pallet,
			benchmark,
			lowest_range_values,
			highest_range_values,
			steps,
			repeat,
			verify,
			extra,
		} = config;
		if &pallet[..] == &name_string[..] {
			$batches.push($crate::BenchmarkBatch {
				pallet: name_string.to_vec(),
				instance: instance_string.to_vec(),
				benchmark: benchmark.clone(),
				results: $( $location )*::run_benchmark(
					&benchmark[..],
					&lowest_range_values[..],
					&highest_range_values[..],
					*steps,
					*repeat,
					whitelist,
					*verify,
				).map_err(|e| {
					$crate::show_benchmark_debug_info(
						instance_string,
						benchmark,
						lowest_range_values,
						highest_range_values,
						steps,
						repeat,
						verify,
						e,
					)
				})?
			});
		}
	)
}

#[macro_export]
macro_rules! list_benchmark {
	( $list:ident, $extra:ident, $name:path, $( $location:tt )* ) => (
		let pallet_string = stringify!($name).as_bytes();
		let instance_string = stringify!( $( $location )* ).as_bytes();
		let benchmarks = $( $location )*::benchmarks($extra)
			.iter()
			.map(|b| b.to_vec())
			.collect::<Vec<_>>();
		let pallet_benchmarks = BenchmarkList {
			pallet: pallet_string.to_vec(),
			instance: instance_string.to_vec(),
			benchmarks: benchmarks.to_vec(),
		};
		$list.push(pallet_benchmarks)
	)
}