core: log chain reorg/split metrics (#18950)

* core: log chain reorg/split metrics

* core: report 1-block reorgs on the metrics too

core/blockchain.go

@@ -64,6 +64,8 @@ var (
 	blockValidationTimer = metrics.NewRegisteredTimer("chain/validation", nil)
 	blockExecutionTimer  = metrics.NewRegisteredTimer("chain/execution", nil)
 	blockWriteTimer      = metrics.NewRegisteredTimer("chain/write", nil)
+	blockReorgAddMeter   = metrics.NewRegisteredMeter("chain/reorg/drop", nil)
+	blockReorgDropMeter  = metrics.NewRegisteredMeter("chain/reorg/add", nil)
 
 	blockPrefetchExecuteTimer   = metrics.NewRegisteredTimer("chain/prefetch/executes", nil)
 	blockPrefetchInterruptMeter = metrics.NewRegisteredMeter("chain/prefetch/interrupts", nil)
@@ -1933,12 +1935,16 @@ func (bc *BlockChain) reorg(oldBlock, newBlock *types.Block) error {
 	}
 	// Ensure the user sees large reorgs
 	if len(oldChain) > 0 && len(newChain) > 0 {
-		logFn := log.Debug
+		logFn := log.Info
+		msg := "Chain reorg detected"
 		if len(oldChain) > 63 {
+			msg = "Large chain reorg detected"
 			logFn = log.Warn
 		}
-		logFn("Chain split detected", "number", commonBlock.Number(), "hash", commonBlock.Hash(),
+		logFn(msg, "number", commonBlock.Number(), "hash", commonBlock.Hash(),
 			"drop", len(oldChain), "dropfrom", oldChain[0].Hash(), "add", len(newChain), "addfrom", newChain[0].Hash())
+		blockReorgAddMeter.Mark(int64(len(newChain)))
+		blockReorgDropMeter.Mark(int64(len(oldChain)))
 	} else {
 		log.Error("Impossible reorg, please file an issue", "oldnum", oldBlock.Number(), "oldhash", oldBlock.Hash(), "newnum", newBlock.Number(), "newhash", newBlock.Hash())
 	}