add --bal.blockingprefetch: if enabled, will ensure that when executing with a BAL, state loading tasks are completed before tx and state root calculation. can be used with --bal.prefetchworkers

cmd/geth/main.go

@@ -160,6 +160,7 @@ var (
 		utils.BeaconCheckpointFileFlag,
 		utils.LogSlowBlockFlag,
 		utils.PrefetchWorkersFlag,
+		utils.BlockingPrefetch,
 	}, utils.NetworkFlags, utils.DatabaseFlags)
 
 	rpcFlags = []cli.Flag{

cmd/utils/flags.go

@@ -721,6 +721,12 @@ var (
 		Category: flags.MiscCategory,
 	}
 
+	BlockingPrefetch = &cli.BoolFlag{
+		Name:     "bal.blockingprefetch",
+		Usage:    "only relevant when executing in parallel with a BAL: if true, the prefetcher will block tx/state-root calculation until all scheduled fetching tasks have completed.",
+		Category: flags.MiscCategory,
+	}
+
 	// RPC settings
 	IPCDisabledFlag = &cli.BoolFlag{
 		Name:     "ipcdisable",
@@ -2467,7 +2473,8 @@ func MakeChain(ctx *cli.Context, stack *node.Node, readonly bool) (*core.BlockCh
 		TrienodeHistory:         ctx.Int64(TrienodeHistoryFlag.Name),
 		NodeFullValueCheckpoint: uint32(ctx.Uint(TrienodeHistoryFullValueCheckpointFlag.Name)),
 
-		PrefetchWorkers: int(ctx.Uint(PrefetchWorkersFlag.Name)),
+		PrefetchWorkers:  int(ctx.Uint(PrefetchWorkersFlag.Name)),
+		BlockingPrefetch: ctx.Bool(BlockingPrefetch.Name),
 		// Disable transaction indexing/unindexing.
 		TxLookupLimit: -1,
 

core/blockchain.go

@@ -211,7 +211,9 @@ type BlockChainConfig struct {
 	Overrides  *ChainOverrides // Optional chain config overrides
 	VmConfig   vm.Config       // Config options for the EVM Interpreter
 
-	PrefetchWorkers int // number of concurrent go-routines for BAL state prefetching
+	// BAL-related
+	PrefetchWorkers  int  // number of concurrent go-routines for BAL state prefetching
+	BlockingPrefetch bool // whether the prefetch should block further execution until it finishes
 
 	// TxLookupLimit specifies the maximum number of blocks from head for which
 	// transaction hashes will be indexed.
@@ -599,7 +601,7 @@ func (bc *BlockChain) processBlockWithAccessList(parentRoot common.Hash, block *
 	useAsyncReads := bc.cfg.BALExecutionMode != bal.BALExecutionNoBatchIO
 	al := block.AccessList() // TODO: make the return of this method not be a pointer
 	accessListReader := bal.NewAccessListReader(*al)
-	prefetchReader, err := sdb.ReaderEIP7928(parentRoot, accessListReader.StorageKeys(useAsyncReads), bc.cfg.PrefetchWorkers)
+	prefetchReader, err := sdb.ReaderEIP7928(parentRoot, accessListReader.StorageKeys(useAsyncReads), bc.cfg.PrefetchWorkers, bc.cfg.BlockingPrefetch)
 	if err != nil {
 		return nil, err
 	}

core/state/database.go

@@ -240,7 +240,7 @@ func (db *CachingDB) ReadersWithCacheStats(stateRoot common.Hash) (Reader, Reade
 }
 
 // ReaderEIP7928 creates a state reader with the manner of Block-level accessList.
-func (db *CachingDB) ReaderEIP7928(stateRoot common.Hash, accessList map[common.Address][]common.Hash, threads int) (Reader, error) {
+func (db *CachingDB) ReaderEIP7928(stateRoot common.Hash, accessList map[common.Address][]common.Hash, threads int, block bool) (Reader, error) {
 	base, err := db.StateReader(stateRoot)
 	if err != nil {
 		return nil, err
@@ -250,6 +250,11 @@ func (db *CachingDB) ReaderEIP7928(stateRoot common.Hash, accessList map[common.
 
 	// Construct the state reader with background prefetching
 	pr := newPrefetchStateReader(r, accessList, threads)
+	if block {
+		if err := pr.Wait(); err != nil {
+			panic("wat do")
+		}
+	}
 
 	return newReaderWithPrefetch(db.codedb.Reader(), pr, pr), nil
 }

tests/block_test_util.go

@@ -162,6 +162,7 @@ func (t *BlockTest) createTestBlockChain(config *params.ChainConfig, snapshotter
 		},
 		StatelessSelfValidation: witness,
 		NoPrefetch:              true,
+		BlockingPrefetch:        true,
 		PrefetchWorkers:         100, // note: this is totally unrelated to NoPrefetch, just for BAL execution
 	}
 	if snapshotter {