Merge pull request #1762 from OffchainLabs/add-gasused-metric

Add gas used since startup to prometheus metric

arbos/block_processor.go

@@ -25,6 +25,7 @@ import (
 	"github.com/ethereum/go-ethereum/core/vm"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/metrics"
 	"github.com/ethereum/go-ethereum/params"
 	"github.com/ethereum/go-ethereum/trie"
 )
@@ -39,6 +40,7 @@ var L2ToL1TransactionEventID common.Hash
 var L2ToL1TxEventID common.Hash
 var EmitReedeemScheduledEvent func(*vm.EVM, uint64, uint64, [32]byte, [32]byte, common.Address, *big.Int, *big.Int) error
 var EmitTicketCreatedEvent func(*vm.EVM, [32]byte) error
+var gasUsedSinceStartupCounter = metrics.NewRegisteredCounter("arb/sequencer/gasused", nil)
 
 type L1Info struct {
 	poster        common.Address
@@ -343,11 +345,7 @@ func ProduceBlockAdvanced(
 			log.Debug("error applying transaction", "tx", tx, "err", err)
 			if !hooks.DiscardInvalidTxsEarly {
 				// we'll still deduct a TxGas's worth from the block-local rate limiter even if the tx was invalid
-				if blockGasLeft > params.TxGas {
-					blockGasLeft -= params.TxGas
-				} else {
-					blockGasLeft = 0
-				}
+				blockGasLeft = arbmath.SaturatingUSub(blockGasLeft, params.TxGas)
 				if isUserTx {
 					userTxsProcessed++
 				}
@@ -416,11 +414,11 @@ func ProduceBlockAdvanced(
 			}
 		}
 
-		if blockGasLeft > computeUsed {
-			blockGasLeft -= computeUsed
-		} else {
-			blockGasLeft = 0
-		}
+		blockGasLeft = arbmath.SaturatingUSub(blockGasLeft, computeUsed)
+
+		// Add gas used since startup to prometheus metric.
+		gasUsed := arbmath.SaturatingUSub(receipt.GasUsed, receipt.GasUsedForL1)
+		gasUsedSinceStartupCounter.Inc(arbmath.SaturatingCast(gasUsed))
 
 		complete = append(complete, tx)
 		receipts = append(receipts, receipt)