diff --git a/blockstore/splitstore/markset.go b/blockstore/splitstore/markset.go
index 218681e13cc..f173be575b4 100644
--- a/blockstore/splitstore/markset.go
+++ b/blockstore/splitstore/markset.go
@@ -10,20 +10,12 @@ import (
 
 var errMarkSetClosed = errors.New("markset closed")
 
-// MarkSet is a utility to keep track of seen CID, and later query for them.
-//
-// * If the expected dataset is large, it can be backed by a datastore (e.g. bbolt).
-// * If a probabilistic result is acceptable, it can be backed by a bloom filter
+// MarkSet is an interface for tracking CIDs during chain and object walks
 type MarkSet interface {
+	ObjectVisitor
 	Mark(cid.Cid) error
 	Has(cid.Cid) (bool, error)
 	Close() error
-	SetConcurrent()
-}
-
-type MarkSetVisitor interface {
-	MarkSet
-	ObjectVisitor
 }
 
 type MarkSetEnv interface {
@@ -31,11 +23,7 @@ type MarkSetEnv interface {
 	// name is a unique name for this markset, mapped to the filesystem in disk-backed environments
 	// sizeHint is a hint about the expected size of the markset
 	Create(name string, sizeHint int64) (MarkSet, error)
-	// CreateVisitor is like Create, but returns a wider interface that supports atomic visits.
-	// It may not be supported by some markset types (e.g. bloom).
-	CreateVisitor(name string, sizeHint int64) (MarkSetVisitor, error)
-	// SupportsVisitor returns true if the marksets created by this environment support the visitor interface.
-	SupportsVisitor() bool
+	// Close closes the markset
 	Close() error
 }
 
diff --git a/blockstore/splitstore/markset_badger.go b/blockstore/splitstore/markset_badger.go
index ae06a69f87e..e30334b8912 100644
--- a/blockstore/splitstore/markset_badger.go
+++ b/blockstore/splitstore/markset_badger.go
@@ -34,7 +34,6 @@ type BadgerMarkSet struct {
 }
 
 var _ MarkSet = (*BadgerMarkSet)(nil)
-var _ MarkSetVisitor = (*BadgerMarkSet)(nil)
 
 var badgerMarkSetBatchSize = 16384
 
@@ -48,7 +47,7 @@ func NewBadgerMarkSetEnv(path string) (MarkSetEnv, error) {
 	return &BadgerMarkSetEnv{path: msPath}, nil
 }
 
-func (e *BadgerMarkSetEnv) create(name string, sizeHint int64) (*BadgerMarkSet, error) {
+func (e *BadgerMarkSetEnv) Create(name string, sizeHint int64) (MarkSet, error) {
 	name += ".tmp"
 	path := filepath.Join(e.path, name)
 
@@ -68,16 +67,6 @@ func (e *BadgerMarkSetEnv) create(name string, sizeHint int64) (*BadgerMarkSet,
 	return ms, nil
 }
 
-func (e *BadgerMarkSetEnv) Create(name string, sizeHint int64) (MarkSet, error) {
-	return e.create(name, sizeHint)
-}
-
-func (e *BadgerMarkSetEnv) CreateVisitor(name string, sizeHint int64) (MarkSetVisitor, error) {
-	return e.create(name, sizeHint)
-}
-
-func (e *BadgerMarkSetEnv) SupportsVisitor() bool { return true }
-
 func (e *BadgerMarkSetEnv) Close() error {
 	return os.RemoveAll(e.path)
 }
diff --git a/blockstore/splitstore/markset_map.go b/blockstore/splitstore/markset_map.go
index 07a7ae70d4c..fda964663ef 100644
--- a/blockstore/splitstore/markset_map.go
+++ b/blockstore/splitstore/markset_map.go
@@ -13,42 +13,27 @@ var _ MarkSetEnv = (*MapMarkSetEnv)(nil)
 type MapMarkSet struct {
 	mx  sync.RWMutex
 	set map[string]struct{}
-
-	ts bool
 }
 
 var _ MarkSet = (*MapMarkSet)(nil)
-var _ MarkSetVisitor = (*MapMarkSet)(nil)
 
 func NewMapMarkSetEnv() (*MapMarkSetEnv, error) {
 	return &MapMarkSetEnv{}, nil
 }
 
-func (e *MapMarkSetEnv) create(name string, sizeHint int64) (*MapMarkSet, error) {
+func (e *MapMarkSetEnv) Create(name string, sizeHint int64) (MarkSet, error) {
 	return &MapMarkSet{
 		set: make(map[string]struct{}, sizeHint),
 	}, nil
 }
 
-func (e *MapMarkSetEnv) Create(name string, sizeHint int64) (MarkSet, error) {
-	return e.create(name, sizeHint)
-}
-
-func (e *MapMarkSetEnv) CreateVisitor(name string, sizeHint int64) (MarkSetVisitor, error) {
-	return e.create(name, sizeHint)
-}
-
-func (e *MapMarkSetEnv) SupportsVisitor() bool { return true }
-
 func (e *MapMarkSetEnv) Close() error {
 	return nil
 }
 
 func (s *MapMarkSet) Mark(cid cid.Cid) error {
-	if s.ts {
-		s.mx.Lock()
-		defer s.mx.Unlock()
-	}
+	s.mx.Lock()
+	defer s.mx.Unlock()
 
 	if s.set == nil {
 		return errMarkSetClosed
@@ -59,10 +44,8 @@ func (s *MapMarkSet) Mark(cid cid.Cid) error {
 }
 
 func (s *MapMarkSet) Has(cid cid.Cid) (bool, error) {
-	if s.ts {
-		s.mx.RLock()
-		defer s.mx.RUnlock()
-	}
+	s.mx.RLock()
+	defer s.mx.RUnlock()
 
 	if s.set == nil {
 		return false, errMarkSetClosed
@@ -73,10 +56,8 @@ func (s *MapMarkSet) Has(cid cid.Cid) (bool, error) {
 }
 
 func (s *MapMarkSet) Visit(c cid.Cid) (bool, error) {
-	if s.ts {
-		s.mx.Lock()
-		defer s.mx.Unlock()
-	}
+	s.mx.Lock()
+	defer s.mx.Unlock()
 
 	if s.set == nil {
 		return false, errMarkSetClosed
@@ -92,14 +73,9 @@ func (s *MapMarkSet) Visit(c cid.Cid) (bool, error) {
 }
 
 func (s *MapMarkSet) Close() error {
-	if s.ts {
-		s.mx.Lock()
-		defer s.mx.Unlock()
-	}
+	s.mx.Lock()
+	defer s.mx.Unlock()
+
 	s.set = nil
 	return nil
 }
-
-func (s *MapMarkSet) SetConcurrent() {
-	s.ts = true
-}
diff --git a/blockstore/splitstore/markset_test.go b/blockstore/splitstore/markset_test.go
index a4a42e8601b..de9421f0894 100644
--- a/blockstore/splitstore/markset_test.go
+++ b/blockstore/splitstore/markset_test.go
@@ -167,7 +167,7 @@ func testMarkSetVisitor(t *testing.T, lsType string) {
 	}
 	defer env.Close() //nolint:errcheck
 
-	visitor, err := env.CreateVisitor("test", 0)
+	visitor, err := env.Create("test", 0)
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/blockstore/splitstore/splitstore.go b/blockstore/splitstore/splitstore.go
index f6715ea333c..62cb2459e54 100644
--- a/blockstore/splitstore/splitstore.go
+++ b/blockstore/splitstore/splitstore.go
@@ -186,10 +186,6 @@ func Open(path string, ds dstore.Datastore, hot, cold bstore.Blockstore, cfg *Co
 		return nil, err
 	}
 
-	if !markSetEnv.SupportsVisitor() {
-		return nil, xerrors.Errorf("markset type does not support atomic visitors")
-	}
-
 	// and now we can make a SplitStore
 	ss := &SplitStore{
 		cfg:        cfg,
diff --git a/blockstore/splitstore/splitstore_check.go b/blockstore/splitstore/splitstore_check.go
index c83ed7b285a..0b4cfe04472 100644
--- a/blockstore/splitstore/splitstore_check.go
+++ b/blockstore/splitstore/splitstore_check.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"sync"
 	"sync/atomic"
 	"time"
 
@@ -67,7 +68,10 @@ func (s *SplitStore) doCheck(curTs *types.TipSet) error {
 	}
 	defer output.Close() //nolint:errcheck
 
+	var mx sync.Mutex
 	write := func(format string, args ...interface{}) {
+		mx.Lock()
+		defer mx.Unlock()
 		_, err := fmt.Fprintf(output, format+"\n", args...)
 		if err != nil {
 			log.Warnf("error writing check output: %s", err)
@@ -82,9 +86,10 @@ func (s *SplitStore) doCheck(curTs *types.TipSet) error {
 	write("compaction index: %d", s.compactionIndex)
 	write("--")
 
-	var coldCnt, missingCnt int64
+	coldCnt := new(int64)
+	missingCnt := new(int64)
 
-	visitor, err := s.markSetEnv.CreateVisitor("check", 0)
+	visitor, err := s.markSetEnv.Create("check", 0)
 	if err != nil {
 		return xerrors.Errorf("error creating visitor: %w", err)
 	}
@@ -111,10 +116,10 @@ func (s *SplitStore) doCheck(curTs *types.TipSet) error {
 			}
 
 			if has {
-				coldCnt++
+				atomic.AddInt64(coldCnt, 1)
 				write("cold object reference: %s", c)
 			} else {
-				missingCnt++
+				atomic.AddInt64(missingCnt, 1)
 				write("missing object reference: %s", c)
 				return errStopWalk
 			}
@@ -128,9 +133,9 @@ func (s *SplitStore) doCheck(curTs *types.TipSet) error {
 		return err
 	}
 
-	log.Infow("check done", "cold", coldCnt, "missing", missingCnt)
+	log.Infow("check done", "cold", *coldCnt, "missing", *missingCnt)
 	write("--")
-	write("cold: %d missing: %d", coldCnt, missingCnt)
+	write("cold: %d missing: %d", *coldCnt, *missingCnt)
 	write("DONE")
 
 	return nil
diff --git a/blockstore/splitstore/splitstore_compact.go b/blockstore/splitstore/splitstore_compact.go
index 13ab90ac006..20f99af35c0 100644
--- a/blockstore/splitstore/splitstore_compact.go
+++ b/blockstore/splitstore/splitstore_compact.go
@@ -5,6 +5,7 @@ import (
 	"errors"
 	"runtime"
 	"sort"
+	"sync"
 	"sync/atomic"
 	"time"
 
@@ -227,7 +228,7 @@ func (s *SplitStore) trackTxnRefMany(cids []cid.Cid) {
 }
 
 // protect all pending transactional references
-func (s *SplitStore) protectTxnRefs(markSet MarkSetVisitor) error {
+func (s *SplitStore) protectTxnRefs(markSet MarkSet) error {
 	for {
 		var txnRefs map[cid.Cid]struct{}
 
@@ -299,14 +300,14 @@ func (s *SplitStore) protectTxnRefs(markSet MarkSetVisitor) error {
 
 // transactionally protect a reference by walking the object and marking.
 // concurrent markings are short circuited by checking the markset.
-func (s *SplitStore) doTxnProtect(root cid.Cid, markSet MarkSetVisitor) error {
+func (s *SplitStore) doTxnProtect(root cid.Cid, markSet MarkSet) error {
 	if err := s.checkClosing(); err != nil {
 		return err
 	}
 
 	// Note: cold objects are deleted heaviest first, so the consituents of an object
 	// cannot be deleted before the object itself.
-	return s.walkObjectIncomplete(root, tmpVisitor(),
+	return s.walkObjectIncomplete(root, newTmpVisitor(),
 		func(c cid.Cid) error {
 			if isUnitaryObject(c) {
 				return errStopWalk
@@ -397,7 +398,7 @@ func (s *SplitStore) doCompact(curTs *types.TipSet) error {
 
 	log.Infow("running compaction", "currentEpoch", currentEpoch, "baseEpoch", s.baseEpoch, "boundaryEpoch", boundaryEpoch, "inclMsgsEpoch", inclMsgsEpoch, "compactionIndex", s.compactionIndex)
 
-	markSet, err := s.markSetEnv.CreateVisitor("live", s.markSetSize)
+	markSet, err := s.markSetEnv.Create("live", s.markSetSize)
 	if err != nil {
 		return xerrors.Errorf("error creating mark set: %w", err)
 	}
@@ -602,8 +603,8 @@ func (s *SplitStore) beginTxnProtect() {
 	s.txnMissing = make(map[cid.Cid]struct{})
 }
 
-func (s *SplitStore) beginTxnMarking(markSet MarkSetVisitor) {
-	markSet.SetConcurrent()
+func (s *SplitStore) beginTxnMarking(markSet MarkSet) {
+	log.Info("beginning transactional marking")
 }
 
 func (s *SplitStore) endTxnProtect() {
@@ -621,26 +622,33 @@ func (s *SplitStore) endTxnProtect() {
 
 func (s *SplitStore) walkChain(ts *types.TipSet, inclState, inclMsgs abi.ChainEpoch,
 	visitor ObjectVisitor, f func(cid.Cid) error) error {
-	var walked *cid.Set
-	toWalk := ts.Cids()
-	walkCnt := 0
-	scanCnt := 0
+	var walked ObjectVisitor
+	var mx sync.Mutex
+	// we copy the tipset first into a new slice, which allows us to reuse it in every epoch.
+	toWalk := make([]cid.Cid, len(ts.Cids()))
+	copy(toWalk, ts.Cids())
+	walkCnt := new(int64)
+	scanCnt := new(int64)
 
 	stopWalk := func(_ cid.Cid) error { return errStopWalk }
 
 	walkBlock := func(c cid.Cid) error {
-		if !walked.Visit(c) {
+		visit, err := walked.Visit(c)
+		if err != nil {
+			return err
+		}
+		if !visit {
 			return nil
 		}
 
-		walkCnt++
+		atomic.AddInt64(walkCnt, 1)
 
 		if err := f(c); err != nil {
 			return err
 		}
 
 		var hdr types.BlockHeader
-		err := s.view(c, func(data []byte) error {
+		err = s.view(c, func(data []byte) error {
 			return hdr.UnmarshalCBOR(bytes.NewBuffer(data))
 		})
 
@@ -676,11 +684,13 @@ func (s *SplitStore) walkChain(ts *types.TipSet, inclState, inclMsgs abi.ChainEp
 			if err := s.walkObject(hdr.ParentStateRoot, visitor, f); err != nil {
 				return xerrors.Errorf("error walking state root (cid: %s): %w", hdr.ParentStateRoot, err)
 			}
-			scanCnt++
+			atomic.AddInt64(scanCnt, 1)
 		}
 
 		if hdr.Height > 0 {
+			mx.Lock()
 			toWalk = append(toWalk, hdr.Parents...)
+			mx.Unlock()
 		}
 
 		return nil
@@ -692,20 +702,43 @@ func (s *SplitStore) walkChain(ts *types.TipSet, inclState, inclMsgs abi.ChainEp
 			return err
 		}
 
+		workers := len(toWalk)
+		if workers > runtime.NumCPU()/2 {
+			workers = runtime.NumCPU() / 2
+		}
+		if workers < 2 {
+			workers = 2
+		}
+
 		// the walk is BFS, so we can reset the walked set in every iteration and avoid building up
 		// a set that contains all blocks (1M epochs -> 5M blocks -> 200MB worth of memory and growing
 		// over time)
-		walked = cid.NewSet()
-		walking := toWalk
-		toWalk = nil
-		for _, c := range walking {
-			if err := walkBlock(c); err != nil {
-				return xerrors.Errorf("error walking block (cid: %s): %w", c, err)
-			}
+		walked = newConcurrentVisitor()
+		workch := make(chan cid.Cid, len(toWalk))
+		for _, c := range toWalk {
+			workch <- c
+		}
+		close(workch)
+		toWalk = toWalk[:0]
+
+		g := new(errgroup.Group)
+		for i := 0; i < workers; i++ {
+			g.Go(func() error {
+				for c := range workch {
+					if err := walkBlock(c); err != nil {
+						return xerrors.Errorf("error walking block (cid: %s): %w", c, err)
+					}
+				}
+				return nil
+			})
+		}
+
+		if err := g.Wait(); err != nil {
+			return err
 		}
 	}
 
-	log.Infow("chain walk done", "walked", walkCnt, "scanned", scanCnt)
+	log.Infow("chain walk done", "walked", *walkCnt, "scanned", *scanCnt)
 
 	return nil
 }
@@ -1011,7 +1044,7 @@ func (s *SplitStore) purgeBatch(cids []cid.Cid, deleteBatch func([]cid.Cid) erro
 	return nil
 }
 
-func (s *SplitStore) purge(cids []cid.Cid, markSet MarkSetVisitor) error {
+func (s *SplitStore) purge(cids []cid.Cid, markSet MarkSet) error {
 	deadCids := make([]cid.Cid, 0, batchSize)
 	var purgeCnt, liveCnt int
 	defer func() {
@@ -1077,7 +1110,7 @@ func (s *SplitStore) purge(cids []cid.Cid, markSet MarkSetVisitor) error {
 // have this gem[TM].
 // My best guess is that they are parent message receipts or yet to be computed state roots; magik
 // thinks the cause may be block validation.
-func (s *SplitStore) waitForMissingRefs(markSet MarkSetVisitor) {
+func (s *SplitStore) waitForMissingRefs(markSet MarkSet) {
 	s.txnLk.Lock()
 	missing := s.txnMissing
 	s.txnMissing = nil
@@ -1106,7 +1139,7 @@ func (s *SplitStore) waitForMissingRefs(markSet MarkSetVisitor) {
 		}
 
 		towalk := missing
-		visitor := tmpVisitor()
+		visitor := newTmpVisitor()
 		missing = make(map[cid.Cid]struct{})
 
 		for c := range towalk {
diff --git a/blockstore/splitstore/splitstore_warmup.go b/blockstore/splitstore/splitstore_warmup.go
index 2a39f6c9d8d..0670bd0f6ff 100644
--- a/blockstore/splitstore/splitstore_warmup.go
+++ b/blockstore/splitstore/splitstore_warmup.go
@@ -1,6 +1,7 @@
 package splitstore
 
 import (
+	"sync"
 	"sync/atomic"
 	"time"
 
@@ -55,12 +56,13 @@ func (s *SplitStore) doWarmup(curTs *types.TipSet) error {
 	if WarmupBoundary < epoch {
 		boundaryEpoch = epoch - WarmupBoundary
 	}
+	var mx sync.Mutex
 	batchHot := make([]blocks.Block, 0, batchSize)
-	count := int64(0)
-	xcount := int64(0)
-	missing := int64(0)
+	count := new(int64)
+	xcount := new(int64)
+	missing := new(int64)
 
-	visitor, err := s.markSetEnv.CreateVisitor("warmup", 0)
+	visitor, err := s.markSetEnv.Create("warmup", 0)
 	if err != nil {
 		return xerrors.Errorf("error creating visitor: %w", err)
 	}
@@ -73,7 +75,7 @@ func (s *SplitStore) doWarmup(curTs *types.TipSet) error {
 				return errStopWalk
 			}
 
-			count++
+			atomic.AddInt64(count, 1)
 
 			has, err := s.hot.Has(s.ctx, c)
 			if err != nil {
@@ -87,22 +89,25 @@ func (s *SplitStore) doWarmup(curTs *types.TipSet) error {
 			blk, err := s.cold.Get(s.ctx, c)
 			if err != nil {
 				if err == bstore.ErrNotFound {
-					missing++
+					atomic.AddInt64(missing, 1)
 					return errStopWalk
 				}
 				return err
 			}
 
-			xcount++
+			atomic.AddInt64(xcount, 1)
 
+			mx.Lock()
 			batchHot = append(batchHot, blk)
 			if len(batchHot) == batchSize {
 				err = s.hot.PutMany(s.ctx, batchHot)
 				if err != nil {
+					mx.Unlock()
 					return err
 				}
 				batchHot = batchHot[:0]
 			}
+			mx.Unlock()
 
 			return nil
 		})
@@ -118,9 +123,9 @@ func (s *SplitStore) doWarmup(curTs *types.TipSet) error {
 		}
 	}
 
-	log.Infow("warmup stats", "visited", count, "warm", xcount, "missing", missing)
+	log.Infow("warmup stats", "visited", *count, "warm", *xcount, "missing", *missing)
 
-	s.markSetSize = count + count>>2 // overestimate a bit
+	s.markSetSize = *count + *count>>2 // overestimate a bit
 	err = s.ds.Put(s.ctx, markSetSizeKey, int64ToBytes(s.markSetSize))
 	if err != nil {
 		log.Warnf("error saving mark set size: %s", err)
diff --git a/blockstore/splitstore/visitor.go b/blockstore/splitstore/visitor.go
index f89c8f3894e..9dfbb78e704 100644
--- a/blockstore/splitstore/visitor.go
+++ b/blockstore/splitstore/visitor.go
@@ -1,6 +1,8 @@
 package splitstore
 
 import (
+	"sync"
+
 	cid "github.com/ipfs/go-cid"
 )
 
@@ -17,16 +19,34 @@ func (v *noopVisitor) Visit(_ cid.Cid) (bool, error) {
 	return true, nil
 }
 
-type cidSetVisitor struct {
+type tmpVisitor struct {
 	set *cid.Set
 }
 
-var _ ObjectVisitor = (*cidSetVisitor)(nil)
+var _ ObjectVisitor = (*tmpVisitor)(nil)
 
-func (v *cidSetVisitor) Visit(c cid.Cid) (bool, error) {
+func (v *tmpVisitor) Visit(c cid.Cid) (bool, error) {
 	return v.set.Visit(c), nil
 }
 
-func tmpVisitor() ObjectVisitor {
-	return &cidSetVisitor{set: cid.NewSet()}
+func newTmpVisitor() ObjectVisitor {
+	return &tmpVisitor{set: cid.NewSet()}
+}
+
+type concurrentVisitor struct {
+	mx  sync.Mutex
+	set *cid.Set
+}
+
+var _ ObjectVisitor = (*concurrentVisitor)(nil)
+
+func newConcurrentVisitor() *concurrentVisitor {
+	return &concurrentVisitor{set: cid.NewSet()}
+}
+
+func (v *concurrentVisitor) Visit(c cid.Cid) (bool, error) {
+	v.mx.Lock()
+	defer v.mx.Unlock()
+
+	return v.set.Visit(c), nil
 }