Computation Cost

Since Klaytn aims to maintain 1-second block time, the execution time of transactions has to be managed. Here are three approaches to achieve that:

  1. Limiting the gas limit of a transaction

  2. Limiting the execution time of a transaction

  3. Limiting the computation cost of a transaction

Limiting the gas limit of a transaction was not a feasible solution because the concept of the gas represents the current exchange value of the various resources in the blockchain platform such as computation, storage, network bandwidth, and so on. It is not suitable as a metric for the transaction execution time.

Limiting the execution time of a transaction was not feasible either because the execution time can vary between nodes on the blockchain platform. For example, consider the case in which we limit the execution time of a transaction to be 100 milli-second. If a node executes a transaction in 90 ms and another node executes it in 110 ms, the two nodes cannot reach a consensus. Hence, this solution is not appropriate.

The last approach is to limit the computation cost of a transaction. We modelled the computation cost of each EVM opcode based on its actual execution time and limit the sum of computation cost of a transaction. With this approach, we eliminate other factors and only count the normalized execution time unit, and nodes can reach a consensus as well.

Therefore, we chose the third option for Klaytn. For now, the limit of the execution cost is set to 100,000,000. Since the limit is determined by the platform, developers should be aware of the computation cost of a transaction. To calculate the computation cost of a transaction, Klaytn provides klay_estimateComputationCost. The usage is almost the same as klay_estimateGas.

Computation Cost of Opcodes

The below table shows the computation cost of EVM opcodes. The computation cost was determined based on experiments.

NOTE: Computation costs have changed with the Kore hardfork. If you want the previous document, please refer to previous document.

Kore hardfork block numbers are as follows.

  • Baobab Testnet: #111736800

  • Cypress Mainnet: #119750400

OpcodeComputationCost

STOP

0

ADD

150

MUL

200

SUB

219

DIV

404

SDIV

739

MOD

812

SMOD

560

ADDMOD

1410

MULMOD

1760

EXP

5000

SIGNEXTEND

481

LT

201

GT

264

SLT

176

SGT

222

EQ

220

ISZERO

165

AND

288

OR

160

XOR

454

NOT

364

BYTE

589

SHL

478

SHR

498

SAR

834

SHA3

2465

ADDRESS

284

BALANCE

1407

ORIGIN

210

CALLER

188

CALLVALUE

149

CALLDATALOAD

596

CALLDATASIZE

194

CALLDATACOPY

100

CODESIZE

145

CODECOPY

898

GASPRICE

131

EXTCODESIZE

1481

EXTCODECOPY

1000

RETURNDATASIZE

10

RETURNDATACOPY

40

EXTCODEHASH

1000

BLOCKHASH

500

COINBASE

189

TIMESTAMP

265

NUMBER

202

PREVRANDAO

1498

GASLIMIT

166

CHAINID

120

SELFBALANCE

374

POP

140

MLOAD

376

MSTORE

288

MSTORE8

5142

SLOAD

835

SSTORE

1548

JUMP

253

JUMPI

176

PC

147

MSIZE

137

GAS

230

JUMPDEST

10

PUSH0

80

PUSH1

120

PUSH2

120

PUSH3

120

PUSH4

120

PUSH5

120

PUSH6

120

PUSH7

120

PUSH8

120

PUSH9

120

PUSH10

120

PUSH11

120

PUSH12

120

PUSH13

120

PUSH14

120

PUSH15

120

PUSH16

120

PUSH17

120

PUSH18

120

PUSH19

120

PUSH20

120

PUSH21

120

PUSH22

120

PUSH23

120

PUSH24

120

PUSH25

120

PUSH26

120

PUSH27

120

PUSH28

120

PUSH29

120

PUSH30

120

PUSH31

120

PUSH32

120

DUP1

190

DUP2

190

DUP3

176

DUP4

142

DUP5

177

DUP6

165

DUP7

147

DUP8

157

DUP9

138

DUP10

174

DUP11

141

DUP12

144

DUP13

157

DUP14

143

DUP15

237

DUP16

149

SWAP1

141

SWAP2

156

SWAP3

145

SWAP4

135

SWAP5

115

SWAP6

146

SWAP7

199

SWAP8

130

SWAP9

160

SWAP10

134

SWAP11

147

SWAP12

128

SWAP13

121

SWAP14

114

SWAP15

197

SWAP16

128

LOG0

100

LOG1

1000

LOG2

1000

LOG3

1000

LOG4

1000

PUSH

0

DUP

0

SWAP

0

CREATE

2094

CALL

5000

CALLCODE

4000

RETURN

0

DELEGATECALL

696

CREATE2

10000

STATICCALL

10000

REVERT

0

SELFDESTRUCT

0

BASEFEE

198

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