diff --git a/chain/actors/actors_test.go b/chain/actors/actors_test.go
index d0f8fba86..30f7b702e 100644
--- a/chain/actors/actors_test.go
+++ b/chain/actors/actors_test.go
@@ -45,7 +45,7 @@ func setupVMTestEnv(t *testing.T) (*vm.VM, []address.Address, bstore.Blockstore)
 		t.Fatal(err)
 	}
 
-	stateroot, err := st.Flush()
+	stateroot, err := st.Flush(context.TODO())
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/chain/actors/harness2_test.go b/chain/actors/harness2_test.go
index 213d1d48e..b51eb234f 100644
--- a/chain/actors/harness2_test.go
+++ b/chain/actors/harness2_test.go
@@ -3,10 +3,11 @@ package actors_test
 import (
 	"bytes"
 	"context"
-	"github.com/filecoin-project/go-sectorbuilder"
 	"math/rand"
 	"testing"
 
+	"github.com/filecoin-project/go-sectorbuilder"
+
 	"github.com/ipfs/go-cid"
 	dstore "github.com/ipfs/go-datastore"
 	hamt "github.com/ipfs/go-hamt-ipld"
@@ -185,7 +186,7 @@ func NewHarness(t *testing.T, options ...HarnessOpt) *Harness {
 		t.Fatal(err)
 	}
 
-	stateroot, err := st.Flush()
+	stateroot, err := st.Flush(context.TODO())
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/chain/blocksync/blocksync.go b/chain/blocksync/blocksync.go
index b810c7783..ce90209d3 100644
--- a/chain/blocksync/blocksync.go
+++ b/chain/blocksync/blocksync.go
@@ -8,7 +8,7 @@ import (
 	"go.opencensus.io/trace"
 	"golang.org/x/xerrors"
 
-	"github.com/filecoin-project/go-cbor-util"
+	cborutil "github.com/filecoin-project/go-cbor-util"
 	"github.com/filecoin-project/lotus/chain/store"
 	"github.com/filecoin-project/lotus/chain/types"
 
diff --git a/chain/blocksync/blocksync_client.go b/chain/blocksync/blocksync_client.go
index f3d681e46..61283a009 100644
--- a/chain/blocksync/blocksync_client.go
+++ b/chain/blocksync/blocksync_client.go
@@ -18,7 +18,7 @@ import (
 	"go.opencensus.io/trace"
 	"golang.org/x/xerrors"
 
-	"github.com/filecoin-project/go-cbor-util"
+	cborutil "github.com/filecoin-project/go-cbor-util"
 	"github.com/filecoin-project/lotus/chain/store"
 	"github.com/filecoin-project/lotus/chain/types"
 	"github.com/filecoin-project/lotus/node/modules/dtypes"
diff --git a/chain/gen/utils.go b/chain/gen/utils.go
index 8b53e7c7a..90f0d1541 100644
--- a/chain/gen/utils.go
+++ b/chain/gen/utils.go
@@ -254,7 +254,7 @@ func SetupStorageMarketActor(bs bstore.Blockstore, sroot cid.Cid, deals []actors
 		return cid.Undef, xerrors.Errorf("set storage market actor: %w", err)
 	}
 
-	return state.Flush()
+	return state.Flush(context.TODO())
 }
 
 type GenMinerCfg struct {
@@ -563,7 +563,7 @@ func MakeGenesisBlock(bs bstore.Blockstore, sys *types.VMSyscalls, balances map[
 		return nil, xerrors.Errorf("make initial state tree failed: %w", err)
 	}
 
-	stateroot, err := state.Flush()
+	stateroot, err := state.Flush(ctx)
 	if err != nil {
 		return nil, xerrors.Errorf("flush state tree failed: %w", err)
 	}
@@ -673,5 +673,5 @@ func AdjustInitActorStartID(ctx context.Context, bs blockstore.Blockstore, state
 		return cid.Undef, err
 	}
 
-	return tree.Flush()
+	return tree.Flush(ctx)
 }
diff --git a/chain/state/statetree.go b/chain/state/statetree.go
index 384af58bb..1dbc0796b 100644
--- a/chain/state/statetree.go
+++ b/chain/state/statetree.go
@@ -7,6 +7,7 @@ import (
 	"github.com/ipfs/go-cid"
 	hamt "github.com/ipfs/go-hamt-ipld"
 	logging "github.com/ipfs/go-log/v2"
+	"go.opencensus.io/trace"
 	"golang.org/x/xerrors"
 
 	"github.com/filecoin-project/go-address"
@@ -116,23 +117,29 @@ func (st *StateTree) GetActor(addr address.Address) (*types.Actor, error) {
 	return &act, nil
 }
 
-func (st *StateTree) Flush() (cid.Cid, error) {
+func (st *StateTree) Flush(ctx context.Context) (cid.Cid, error) {
+	ctx, span := trace.StartSpan(ctx, "stateTree.Flush")
+	defer span.End()
+
 	for addr, act := range st.actorcache {
-		if err := st.root.Set(context.TODO(), string(addr.Bytes()), act); err != nil {
+		if err := st.root.Set(ctx, string(addr.Bytes()), act); err != nil {
 			return cid.Undef, err
 		}
 	}
 	st.actorcache = make(map[address.Address]*types.Actor)
 
-	if err := st.root.Flush(context.TODO()); err != nil {
+	if err := st.root.Flush(ctx); err != nil {
 		return cid.Undef, err
 	}
 
-	return st.Store.Put(context.TODO(), st.root)
+	return st.Store.Put(ctx, st.root)
 }
 
-func (st *StateTree) Snapshot() error {
-	ss, err := st.Flush()
+func (st *StateTree) Snapshot(ctx context.Context) error {
+	ctx, span := trace.StartSpan(ctx, "stateTree.SnapShot")
+	defer span.End()
+
+	ss, err := st.Flush(ctx)
 	if err != nil {
 		return err
 	}
diff --git a/chain/state/statetree_test.go b/chain/state/statetree_test.go
index a12bbbeca..17d71daca 100644
--- a/chain/state/statetree_test.go
+++ b/chain/state/statetree_test.go
@@ -1,6 +1,7 @@
 package state
 
 import (
+	"context"
 	"testing"
 
 	address "github.com/filecoin-project/go-address"
@@ -60,7 +61,7 @@ func BenchmarkStateTreeSetFlush(b *testing.B) {
 		if err != nil {
 			b.Fatal(err)
 		}
-		if _, err := st.Flush(); err != nil {
+		if _, err := st.Flush(context.TODO()); err != nil {
 			b.Fatal(err)
 		}
 	}
@@ -88,7 +89,7 @@ func BenchmarkStateTree10kGetActor(b *testing.B) {
 		}
 	}
 
-	if _, err := st.Flush(); err != nil {
+	if _, err := st.Flush(context.TODO()); err != nil {
 		b.Fatal(err)
 	}
 
diff --git a/chain/stmgr/forks.go b/chain/stmgr/forks.go
index acd7f974b..2db04c695 100644
--- a/chain/stmgr/forks.go
+++ b/chain/stmgr/forks.go
@@ -91,7 +91,7 @@ func fixBlizzardAMTBug(ctx context.Context, sm *StateManager, pstate cid.Cid) (c
 		}
 	}
 
-	return st.Flush()
+	return st.Flush(ctx)
 }
 
 func fixMiner(ctx context.Context, cst *hamt.CborIpldStore, bs blockstore.Blockstore, mscid cid.Cid) (cid.Cid, error) {
diff --git a/chain/validation/state.go b/chain/validation/state.go
index f03aee5d8..53600abbb 100644
--- a/chain/validation/state.go
+++ b/chain/validation/state.go
@@ -59,7 +59,7 @@ func NewState() *StateWrapper {
 	if err != nil {
 		panic(err) // Never returns error, the error return should be removed.
 	}
-	root, err := treeImpl.Flush()
+	root, err := treeImpl.Flush(context.TODO())
 	if err != nil {
 		panic(err)
 	}
@@ -208,7 +208,7 @@ func (s *StateWrapper) Signer() *keyStore {
 
 // Flushes a state tree to storage and sets this state's root to that tree's root CID.
 func (s *StateWrapper) flush(tree *state.StateTree) (err error) {
-	s.stateRoot, err = tree.Flush()
+	s.stateRoot, err = tree.Flush(context.TODO())
 	return
 }
 
diff --git a/chain/vm/vm.go b/chain/vm/vm.go
index ba67c922c..176355689 100644
--- a/chain/vm/vm.go
+++ b/chain/vm/vm.go
@@ -430,7 +430,7 @@ func (vm *VM) ApplyMessage(ctx context.Context, msg *types.Message) (*ApplyRet,
 	}
 
 	st := vm.cstate
-	if err := st.Snapshot(); err != nil {
+	if err := st.Snapshot(ctx); err != nil {
 		return nil, xerrors.Errorf("snapshot failed: %w", err)
 	}
 
@@ -534,7 +534,7 @@ func (vm *VM) Flush(ctx context.Context) (cid.Cid, error) {
 	from := vm.buf
 	to := vm.buf.Read()
 
-	root, err := vm.cstate.Flush()
+	root, err := vm.cstate.Flush(ctx)
 	if err != nil {
 		return cid.Undef, xerrors.Errorf("flushing vm: %w", err)
 	}
diff --git a/cmd/lotus/daemon.go b/cmd/lotus/daemon.go
index cab9250b9..8e38ff90f 100644
--- a/cmd/lotus/daemon.go
+++ b/cmd/lotus/daemon.go
@@ -6,6 +6,7 @@ import (
 	"context"
 	"io/ioutil"
 	"os"
+	"runtime/pprof"
 
 	paramfetch "github.com/filecoin-project/go-paramfetch"
 	"github.com/filecoin-project/go-sectorbuilder"
@@ -70,8 +71,24 @@ var DaemonCmd = &cli.Command{
 			Name:  "halt-after-import",
 			Usage: "halt the process after importing chain from file",
 		},
+		&cli.StringFlag{
+			Name:  "pprof",
+			Usage: "specify name of file for writing cpu profile to",
+		},
 	},
 	Action: func(cctx *cli.Context) error {
+		if prof := cctx.String("pprof"); prof != "" {
+			profile, err := os.Create(prof)
+			if err != nil {
+				return err
+			}
+
+			if err := pprof.StartCPUProfile(profile); err != nil {
+				return err
+			}
+			defer pprof.StopCPUProfile()
+		}
+
 		ctx := context.Background()
 		r, err := repo.NewFS(cctx.String("repo"))
 		if err != nil {