pub struct TargetedFeeAdjustment<T, S, V, M, X>(_);
Expand description

A struct to update the weight multiplier per block. It implements Convert<Multiplier, Multiplier>, meaning that it can convert the previous multiplier to the next one. This should be called on on_finalize of a block, prior to potentially cleaning the weight data from the system pallet.

given: s = previous block weight s’= ideal block weight m = maximum block weight diff = (s - s’)/m v = 0.00001 t1 = (v * diff) t2 = (v * diff)^2 / 2 then: next_multiplier = prev_multiplier * (1 + t1 + t2)

Where (s', v) must be given as the Get implementation of the T generic type. Moreover, M must provide the minimum allowed value for the multiplier. Note that a runtime should ensure with tests that the combination of this M and V is not such that the multiplier can drop to zero and never recover.

Note that s' is interpreted as a portion in the normal transaction capacity of the block. For example, given s' == 0.25 and AvailableBlockRatio = 0.75, then the target fullness is 0.25 of the normal capacity and 0.1875 of the entire block.

Since block weight is multi-dimension, we use the scarcer resource, referred as limiting dimension, for calculation of fees. We determine the limiting dimension by comparing the dimensions using the ratio of dimension_value / max_dimension_value and selecting the largest ratio. For instance, if a block is 30% full based on ref_time and 25% full based on proof_size, we identify ref_time as the limiting dimension, indicating that the block is 30% full.

This implementation implies the bound:

  • v ≤ p / k * (s − s')
  • or, solving for p: p >= v * k * (s - s')

where p is the amount of change over k blocks.

Hence:

  • in a fully congested chain: p >= v * k * (1 - s').
  • in an empty chain: p >= v * k * (-s').

For example, when all blocks are full and there are 28800 blocks per day (default in substrate-node) and v == 0.00001, s’ == 0.1875, we’d have:

p >= 0.00001 * 28800 * 0.8125 p >= 0.234

Meaning that fees can change by around ~23% per day, given extreme congestion.

More info can be found at: https://research.web3.foundation/en/latest/polkadot/overview/2-token-economics.html

Trait Implementations§

source§

impl<T, S, V, M, X> Convert<FixedU128, FixedU128> for TargetedFeeAdjustment<T, S, V, M, X>where T: Config, S: Get<Perquintill>, V: Get<FixedU128>, M: Get<FixedU128>, X: Get<FixedU128>,

source§

fn convert(previous: FixedU128) -> FixedU128

Make conversion.
source§

impl<T, S, V, M, X> MultiplierUpdate for TargetedFeeAdjustment<T, S, V, M, X>where T: Config, S: Get<Perquintill>, V: Get<FixedU128>, M: Get<FixedU128>, X: Get<FixedU128>,

source§

fn min() -> FixedU128

Minimum multiplier. Any outcome of the convert function should be at least this.
source§

fn max() -> FixedU128

Maximum multiplier. Any outcome of the convert function should be less or equal this.
source§

fn target() -> Perquintill

Target block saturation level
source§

fn variability() -> FixedU128

Variability factor

Auto Trait Implementations§

§

impl<T, S, V, M, X> RefUnwindSafe for TargetedFeeAdjustment<T, S, V, M, X>where M: RefUnwindSafe, S: RefUnwindSafe, T: RefUnwindSafe, V: RefUnwindSafe, X: RefUnwindSafe,

§

impl<T, S, V, M, X> Send for TargetedFeeAdjustment<T, S, V, M, X>where M: Send, S: Send, T: Send, V: Send, X: Send,

§

impl<T, S, V, M, X> Sync for TargetedFeeAdjustment<T, S, V, M, X>where M: Sync, S: Sync, T: Sync, V: Sync, X: Sync,

§

impl<T, S, V, M, X> Unpin for TargetedFeeAdjustment<T, S, V, M, X>where M: Unpin, S: Unpin, T: Unpin, V: Unpin, X: Unpin,

§

impl<T, S, V, M, X> UnwindSafe for TargetedFeeAdjustment<T, S, V, M, X>where M: UnwindSafe, S: UnwindSafe, T: UnwindSafe, V: UnwindSafe, X: UnwindSafe,

Blanket Implementations§

source§

impl<T> Any for Twhere T: 'static + ?Sized,

source§

fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
§

impl<T> Any for Twhere T: Any,

§

fn into_any(self: Box<T, Global>) -> Box<dyn Any + 'static, Global>

§

fn into_any_rc(self: Rc<T>) -> Rc<dyn Any + 'static>

§

fn type_name(&self) -> &'static str

§

impl<T> AnySync for Twhere T: Any + Send + Sync,

§

fn into_any_arc(self: Arc<T>) -> Arc<dyn Any + Sync + Send + 'static>

source§

impl<T> Borrow<T> for Twhere T: ?Sized,

const: unstable · source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
source§

impl<T> BorrowMut<T> for Twhere T: ?Sized,

const: unstable · source§

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
source§

impl<T> CheckedConversion for T

source§

fn checked_from<T>(t: T) -> Option<Self>where Self: TryFrom<T>,

Convert from a value of T into an equivalent instance of Option<Self>. Read more
source§

fn checked_into<T>(self) -> Option<T>where Self: TryInto<T>,

Consume self to return Some equivalent value of Option<T>. Read more
§

impl<T> Downcast for Twhere T: Any,

§

fn into_any(self: Box<T, Global>) -> Box<dyn Any + 'static, Global>

Convert Box<dyn Trait> (where Trait: Downcast) to Box<dyn Any>. Box<dyn Any> can then be further downcast into Box<ConcreteType> where ConcreteType implements Trait.
§

fn into_any_rc(self: Rc<T>) -> Rc<dyn Any + 'static>

Convert Rc<Trait> (where Trait: Downcast) to Rc<Any>. Rc<Any> can then be further downcast into Rc<ConcreteType> where ConcreteType implements Trait.
§

fn as_any(&self) -> &(dyn Any + 'static)

Convert &Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &Any’s vtable from &Trait’s.
§

fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)

Convert &mut Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &mut Any’s vtable from &mut Trait’s.
§

impl<T> DowncastSync for Twhere T: Any + Send + Sync,

§

fn into_any_arc(self: Arc<T>) -> Arc<dyn Any + Sync + Send + 'static>

Convert Arc<Trait> (where Trait: Downcast) to Arc<Any>. Arc<Any> can then be further downcast into Arc<ConcreteType> where ConcreteType implements Trait.
source§

impl<T> From<T> for T

const: unstable · source§

fn from(t: T) -> T

Returns the argument unchanged.

source§

impl<T> Instrument for T

source§

fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
source§

fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
source§

impl<T, U> Into<U> for Twhere U: From<T>,

const: unstable · source§

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

source§

impl<T> IsType<T> for T

source§

fn from_ref(t: &T) -> &T

Cast reference.
source§

fn into_ref(&self) -> &T

Cast reference.
source§

fn from_mut(t: &mut T) -> &mut T

Cast mutable reference.
source§

fn into_mut(&mut self) -> &mut T

Cast mutable reference.
source§

impl<T, Outer> IsWrappedBy<Outer> for Twhere Outer: AsRef<T> + AsMut<T> + From<T>, T: From<Outer>,

source§

fn from_ref(outer: &Outer) -> &T

Get a reference to the inner from the outer.

source§

fn from_mut(outer: &mut Outer) -> &mut T

Get a mutable reference to the inner from the outer.

§

impl<T> Pointable for T

§

const ALIGN: usize = mem::align_of::<T>()

The alignment of pointer.
§

type Init = T

The type for initializers.
§

unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
§

unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
§

unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
§

unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
source§

impl<T> Same<T> for T

§

type Output = T

Should always be Self
source§

impl<T> SaturatedConversion for T

source§

fn saturated_from<T>(t: T) -> Selfwhere Self: UniqueSaturatedFrom<T>,

Convert from a value of T into an equivalent instance of Self. Read more
source§

fn saturated_into<T>(self) -> Twhere Self: UniqueSaturatedInto<T>,

Consume self to return an equivalent value of T. Read more
§

impl<SS, SP> SupersetOf<SS> for SPwhere SS: SubsetOf<SP>,

§

fn to_subset(&self) -> Option<SS>

The inverse inclusion map: attempts to construct self from the equivalent element of its superset. Read more
§

fn is_in_subset(&self) -> bool

Checks if self is actually part of its subset T (and can be converted to it).
§

fn to_subset_unchecked(&self) -> SS

Use with care! Same as self.to_subset but without any property checks. Always succeeds.
§

fn from_subset(element: &SS) -> SP

The inclusion map: converts self to the equivalent element of its superset.
source§

impl<T, U> TryFrom<U> for Twhere U: Into<T>,

§

type Error = Infallible

The type returned in the event of a conversion error.
const: unstable · source§

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
source§

impl<T, U> TryInto<U> for Twhere U: TryFrom<T>,

§

type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
const: unstable · source§

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
source§

impl<S, T> UncheckedInto<T> for Swhere T: UncheckedFrom<S>,

source§

fn unchecked_into(self) -> T

The counterpart to unchecked_from.
source§

impl<T, S> UniqueSaturatedInto<T> for Swhere T: Bounded, S: TryInto<T>,

source§

fn unique_saturated_into(self) -> T

Consume self to return an equivalent value of T.
§

impl<V, T> VZip<V> for Twhere V: MultiLane<T>,

§

fn vzip(self) -> V

source§

impl<T> WithSubscriber for T

source§

fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>where S: Into<Dispatch>,

Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
source§

fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more
§

impl<T> JsonSchemaMaybe for T

source§

impl<T> MaybeRefUnwindSafe for Twhere T: RefUnwindSafe,

§

impl<T> MaybeSend for Twhere T: Send,