core: add gauge metrics + histograms for block gas used and blob gas used (#705)

* core: add gauge metric for block gas used and blob gas used

This can be used to track the DA footprint per block

* encapsulate OPStack additions into new file and function

* add histogram metrics for (blob)GasUsed

* update fork.yaml

* typos

Author: geoknee

core/blockchain.go

@@ -64,7 +64,6 @@ var (
 	headFastBlockGauge      = metrics.NewRegisteredGauge("chain/head/receipt", nil)
 	headFinalizedBlockGauge = metrics.NewRegisteredGauge("chain/head/finalized", nil)
 	headSafeBlockGauge      = metrics.NewRegisteredGauge("chain/head/safe", nil)
-	headBaseFeeGauge        = metrics.NewRegisteredGauge("chain/head/basefee", nil)
 
 	chainInfoGauge   = metrics.NewRegisteredGaugeInfo("chain/info", nil)
 	chainMgaspsMeter = metrics.NewRegisteredResettingTimer("chain/mgasps", nil)
@@ -1230,7 +1229,9 @@ func (bc *BlockChain) writeHeadBlock(block *types.Block) {
 
 	bc.currentBlock.Store(block.Header())
 	headBlockGauge.Update(int64(block.NumberU64()))
-	headBaseFeeGauge.TryUpdate(block.Header().BaseFee)
+
+	// OPStack addition
+	updateOptimismBlockMetrics(block.Header())
 }
 
 // stopWithoutSaving stops the blockchain service. If any imports are currently in progress
@@ -1398,7 +1399,9 @@ func (bc *BlockChain) InsertReceiptChain(blockChain types.Blocks, receiptChain [
 		bc.currentSnapBlock.Store(header)
 		headHeaderGauge.Update(header.Number.Int64())
 		headFastBlockGauge.Update(header.Number.Int64())
-		headBaseFeeGauge.TryUpdate(header.BaseFee)
+
+		// OPStack addition
+		updateOptimismBlockMetrics(header)
 		return nil
 	}
 	// writeAncient writes blockchain and corresponding receipt chain into ancient store.
@@ -2771,7 +2774,9 @@ func (bc *BlockChain) InsertHeadersBeforeCutoff(headers []*types.Header) (int, e
 	bc.currentSnapBlock.Store(last)
 	headHeaderGauge.Update(last.Number.Int64())
 	headFastBlockGauge.Update(last.Number.Int64())
-	headBaseFeeGauge.TryUpdate(last.BaseFee)
+
+	// OPStack addition
+	updateOptimismBlockMetrics(last)
 	return 0, nil
 }
 

core/blockchain_optimism.go

@@ -0,0 +1,27 @@
+package core
+
+import (
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/metrics"
+)
+
+// OPStack additions
+var (
+	headBaseFeeGauge     = metrics.NewRegisteredGauge("chain/head/basefee", nil)
+	headGasUsedGauge     = metrics.NewRegisteredGauge("chain/head/gas_used", nil)
+	headBlobGasUsedGauge = metrics.NewRegisteredGauge("chain/head/blob_gas_used", nil)
+
+	headGasUsedHist     = metrics.NewRegisteredHistogram("chain/head/gas_used_hist", nil, metrics.NewExpDecaySample(1028, 0.015))
+	headBlobGasUsedHist = metrics.NewRegisteredHistogram("chain/head/blob_gas_used_hist", nil, metrics.NewExpDecaySample(1028, 0.015))
+)
+
+func updateOptimismBlockMetrics(header *types.Header) error {
+	headBaseFeeGauge.TryUpdate(header.BaseFee)
+	headGasUsedGauge.Update(int64(header.GasUsed))
+	headBlobGasUsedGauge.TryUpdateUint64(header.BlobGasUsed)
+	headGasUsedHist.Update(int64(header.GasUsed))
+	if header.BlobGasUsed != nil {
+		headBlobGasUsedHist.Update(int64(*header.BlobGasUsed))
+	}
+	return nil
+}

core/headerchain.go

@@ -92,7 +92,9 @@ func NewHeaderChain(chainDb ethdb.Database, config *params.ChainConfig, engine c
 	}
 	hc.currentHeaderHash = hc.CurrentHeader().Hash()
 	headHeaderGauge.Update(hc.CurrentHeader().Number.Int64())
-	headBaseFeeGauge.TryUpdate(hc.CurrentHeader().BaseFee)
+
+	// OPStack addition
+	updateOptimismBlockMetrics(hc.CurrentHeader())
 	return hc, nil
 }
 
@@ -183,7 +185,9 @@ func (hc *HeaderChain) Reorg(headers []*types.Header) error {
 	hc.currentHeaderHash = last.Hash()
 	hc.currentHeader.Store(types.CopyHeader(last))
 	headHeaderGauge.Update(last.Number.Int64())
-	headBaseFeeGauge.TryUpdate(last.BaseFee)
+
+	// OPStack addition
+	updateOptimismBlockMetrics(last)
 	return nil
 }
 
@@ -486,7 +490,9 @@ func (hc *HeaderChain) SetCurrentHeader(head *types.Header) {
 	hc.currentHeader.Store(head)
 	hc.currentHeaderHash = head.Hash()
 	headHeaderGauge.Update(head.Number.Int64())
-	headBaseFeeGauge.TryUpdate(head.BaseFee)
+
+	// OPStack addition
+	updateOptimismBlockMetrics(head)
 }
 
 type (
@@ -573,7 +579,9 @@ func (hc *HeaderChain) setHead(headBlock uint64, headTime uint64, updateFn Updat
 		hc.currentHeader.Store(parent)
 		hc.currentHeaderHash = parentHash
 		headHeaderGauge.Update(parent.Number.Int64())
-		headBaseFeeGauge.TryUpdate(parent.BaseFee)
+
+		// OPStack addition
+		updateOptimismBlockMetrics(parent)
 
 		// If this is the first iteration, wipe any leftover data upwards too so
 		// we don't end up with dangling daps in the database

fork.yaml

@@ -199,7 +199,10 @@ def:
         - title: Warn on missing hardfork data and emit additional metrics
           globs:
             - "core/blockchain.go"
-        - title: Additional metrics
+        - title: Define additional header-based metrics
+          globs:
+            - "core/blockchain_optimism.go"
+        - title: Add hooks for additional header-chain metrics
           globs:
             - "core/headerchain.go"
         - title: Optional Engine API extensions

metrics/gauge.go

@@ -45,6 +45,7 @@ func (g *Gauge) Update(v int64) {
 	(*atomic.Int64)(g).Store(v)
 }
 
+// OPStack addition
 // TryUpdate updates the gauge if the value is non-nil, converting it to int64.
 func (g *Gauge) TryUpdate(v *big.Int) {
 	if v == nil {
@@ -53,6 +54,15 @@ func (g *Gauge) TryUpdate(v *big.Int) {
 	(*atomic.Int64)(g).Store(v.Int64())
 }
 
+// OPStack additon
+// TryUpdate updates the gauge if the value is non-nil, converting it to int64.
+func (g *Gauge) TryUpdateUint64(v *uint64) {
+	if v == nil {
+		return
+	}
+	(*atomic.Int64)(g).Store(int64(*v))
+}
+
 // UpdateIfGt updates the gauge's value if v is larger then the current value.
 func (g *Gauge) UpdateIfGt(v int64) {
 	value := (*atomic.Int64)(g)