eth/gasestimator: allow slight estimation error in favor of less iterations (#28618)

* eth/gasestimator: early exit for plain transfer and error allowance

* core, eth/gasestimator: hard guess at a possible required gas

* internal/ethapi: update estimation tests with the error ratio

* eth/gasestimator: I hate you linter

* graphql: fix gas estimation test

---------

Co-authored-by: Oren <orenyomtov@users.noreply.github.com>
This commit is contained in:
Péter Szilágyi 2023-11-28 22:31:47 +02:00 committed by GitHub
parent e0c7ad01ab
commit 61b844f2b2
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GPG Key ID: 4AEE18F83AFDEB23
5 changed files with 68 additions and 17 deletions

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@ -32,9 +32,10 @@ import (
// ExecutionResult includes all output after executing given evm // ExecutionResult includes all output after executing given evm
// message no matter the execution itself is successful or not. // message no matter the execution itself is successful or not.
type ExecutionResult struct { type ExecutionResult struct {
UsedGas uint64 // Total used gas but include the refunded gas UsedGas uint64 // Total used gas, not including the refunded gas
Err error // Any error encountered during the execution(listed in core/vm/errors.go) RefundedGas uint64 // Total gas refunded after execution
ReturnData []byte // Returned data from evm(function result or data supplied with revert opcode) Err error // Any error encountered during the execution(listed in core/vm/errors.go)
ReturnData []byte // Returned data from evm(function result or data supplied with revert opcode)
} }
// Unwrap returns the internal evm error which allows us for further // Unwrap returns the internal evm error which allows us for further
@ -419,12 +420,13 @@ func (st *StateTransition) TransitionDb() (*ExecutionResult, error) {
ret, st.gasRemaining, vmerr = st.evm.Call(sender, st.to(), msg.Data, st.gasRemaining, msg.Value) ret, st.gasRemaining, vmerr = st.evm.Call(sender, st.to(), msg.Data, st.gasRemaining, msg.Value)
} }
var gasRefund uint64
if !rules.IsLondon { if !rules.IsLondon {
// Before EIP-3529: refunds were capped to gasUsed / 2 // Before EIP-3529: refunds were capped to gasUsed / 2
st.refundGas(params.RefundQuotient) gasRefund = st.refundGas(params.RefundQuotient)
} else { } else {
// After EIP-3529: refunds are capped to gasUsed / 5 // After EIP-3529: refunds are capped to gasUsed / 5
st.refundGas(params.RefundQuotientEIP3529) gasRefund = st.refundGas(params.RefundQuotientEIP3529)
} }
effectiveTip := msg.GasPrice effectiveTip := msg.GasPrice
if rules.IsLondon { if rules.IsLondon {
@ -442,13 +444,14 @@ func (st *StateTransition) TransitionDb() (*ExecutionResult, error) {
} }
return &ExecutionResult{ return &ExecutionResult{
UsedGas: st.gasUsed(), UsedGas: st.gasUsed(),
Err: vmerr, RefundedGas: gasRefund,
ReturnData: ret, Err: vmerr,
ReturnData: ret,
}, nil }, nil
} }
func (st *StateTransition) refundGas(refundQuotient uint64) { func (st *StateTransition) refundGas(refundQuotient uint64) uint64 {
// Apply refund counter, capped to a refund quotient // Apply refund counter, capped to a refund quotient
refund := st.gasUsed() / refundQuotient refund := st.gasUsed() / refundQuotient
if refund > st.state.GetRefund() { if refund > st.state.GetRefund() {
@ -463,6 +466,8 @@ func (st *StateTransition) refundGas(refundQuotient uint64) {
// Also return remaining gas to the block gas counter so it is // Also return remaining gas to the block gas counter so it is
// available for the next transaction. // available for the next transaction.
st.gp.AddGas(st.gasRemaining) st.gp.AddGas(st.gasRemaining)
return refund
} }
// gasUsed returns the amount of gas used up by the state transition. // gasUsed returns the amount of gas used up by the state transition.

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@ -42,6 +42,8 @@ type Options struct {
Chain core.ChainContext // Chain context to access past block hashes Chain core.ChainContext // Chain context to access past block hashes
Header *types.Header // Header defining the block context to execute in Header *types.Header // Header defining the block context to execute in
State *state.StateDB // Pre-state on top of which to estimate the gas State *state.StateDB // Pre-state on top of which to estimate the gas
ErrorRatio float64 // Allowed overestimation ratio for faster estimation termination
} }
// Estimate returns the lowest possible gas limit that allows the transaction to // Estimate returns the lowest possible gas limit that allows the transaction to
@ -86,16 +88,28 @@ func Estimate(ctx context.Context, call *core.Message, opts *Options, gasCap uin
if transfer == nil { if transfer == nil {
transfer = new(big.Int) transfer = new(big.Int)
} }
log.Warn("Gas estimation capped by limited funds", "original", hi, "balance", balance, log.Debug("Gas estimation capped by limited funds", "original", hi, "balance", balance,
"sent", transfer, "maxFeePerGas", feeCap, "fundable", allowance) "sent", transfer, "maxFeePerGas", feeCap, "fundable", allowance)
hi = allowance.Uint64() hi = allowance.Uint64()
} }
} }
// Recap the highest gas allowance with specified gascap. // Recap the highest gas allowance with specified gascap.
if gasCap != 0 && hi > gasCap { if gasCap != 0 && hi > gasCap {
log.Warn("Caller gas above allowance, capping", "requested", hi, "cap", gasCap) log.Debug("Caller gas above allowance, capping", "requested", hi, "cap", gasCap)
hi = gasCap hi = gasCap
} }
// If the transaction is a plain value transfer, short circuit estimation and
// directly try 21000. Returning 21000 without any execution is dangerous as
// some tx field combos might bump the price up even for plain transfers (e.g.
// unused access list items). Ever so slightly wasteful, but safer overall.
if len(call.Data) == 0 {
if call.To != nil && opts.State.GetCodeSize(*call.To) == 0 {
failed, _, err := execute(ctx, call, opts, params.TxGas)
if !failed && err == nil {
return params.TxGas, nil, nil
}
}
}
// We first execute the transaction at the highest allowable gas limit, since if this fails we // We first execute the transaction at the highest allowable gas limit, since if this fails we
// can return error immediately. // can return error immediately.
failed, result, err := execute(ctx, call, opts, hi) failed, result, err := execute(ctx, call, opts, hi)
@ -115,8 +129,35 @@ func Estimate(ctx context.Context, call *core.Message, opts *Options, gasCap uin
// limit for these cases anyway. // limit for these cases anyway.
lo = result.UsedGas - 1 lo = result.UsedGas - 1
// There's a fairly high chance for the transaction to execute successfully
// with gasLimit set to the first execution's usedGas + gasRefund. Explicitly
// check that gas amount and use as a limit for the binary search.
optimisticGasLimit := (result.UsedGas + result.RefundedGas + params.CallStipend) * 64 / 63
if optimisticGasLimit < hi {
failed, _, err = execute(ctx, call, opts, optimisticGasLimit)
if err != nil {
// This should not happen under normal conditions since if we make it this far the
// transaction had run without error at least once before.
log.Error("Execution error in estimate gas", "err", err)
return 0, nil, err
}
if failed {
lo = optimisticGasLimit
} else {
hi = optimisticGasLimit
}
}
// Binary search for the smallest gas limit that allows the tx to execute successfully. // Binary search for the smallest gas limit that allows the tx to execute successfully.
for lo+1 < hi { for lo+1 < hi {
if opts.ErrorRatio > 0 {
// It is a bit pointless to return a perfect estimation, as changing
// network conditions require the caller to bump it up anyway. Since
// wallets tend to use 20-25% bump, allowing a small approximation
// error is fine (as long as it's upwards).
if float64(hi-lo)/float64(hi) < opts.ErrorRatio {
break
}
}
mid := (hi + lo) / 2 mid := (hi + lo) / 2
if mid > lo*2 { if mid > lo*2 {
// Most txs don't need much higher gas limit than their gas used, and most txs don't // Most txs don't need much higher gas limit than their gas used, and most txs don't

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@ -139,7 +139,7 @@ func TestGraphQLBlockSerialization(t *testing.T) {
// should return `estimateGas` as decimal // should return `estimateGas` as decimal
{ {
body: `{"query": "{block{ estimateGas(data:{}) }}"}`, body: `{"query": "{block{ estimateGas(data:{}) }}"}`,
want: `{"data":{"block":{"estimateGas":"0xcf08"}}}`, want: `{"data":{"block":{"estimateGas":"0xd221"}}}`,
code: 200, code: 200,
}, },
// should return `status` as decimal // should return `status` as decimal

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@ -51,6 +51,10 @@ import (
"github.com/tyler-smith/go-bip39" "github.com/tyler-smith/go-bip39"
) )
// estimateGasErrorRatio is the amount of overestimation eth_estimateGas is
// allowed to produce in order to speed up calculations.
const estimateGasErrorRatio = 0.015
// EthereumAPI provides an API to access Ethereum related information. // EthereumAPI provides an API to access Ethereum related information.
type EthereumAPI struct { type EthereumAPI struct {
b Backend b Backend
@ -1189,10 +1193,11 @@ func DoEstimateGas(ctx context.Context, b Backend, args TransactionArgs, blockNr
} }
// Construct the gas estimator option from the user input // Construct the gas estimator option from the user input
opts := &gasestimator.Options{ opts := &gasestimator.Options{
Config: b.ChainConfig(), Config: b.ChainConfig(),
Chain: NewChainContext(ctx, b), Chain: NewChainContext(ctx, b),
Header: header, Header: header,
State: state, State: state,
ErrorRatio: estimateGasErrorRatio,
} }
// Run the gas estimation andwrap any revertals into a custom return // Run the gas estimation andwrap any revertals into a custom return
call, err := args.ToMessage(gasCap, header.BaseFee) call, err := args.ToMessage(gasCap, header.BaseFee)

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@ -735,7 +735,7 @@ func TestEstimateGas(t *testing.T) {
t.Errorf("test %d: want no error, have %v", i, err) t.Errorf("test %d: want no error, have %v", i, err)
continue continue
} }
if uint64(result) != tc.want { if float64(result) > float64(tc.want)*(1+estimateGasErrorRatio) {
t.Errorf("test %d, result mismatch, have\n%v\n, want\n%v\n", i, uint64(result), tc.want) t.Errorf("test %d, result mismatch, have\n%v\n, want\n%v\n", i, uint64(result), tc.want)
} }
} }