diff --git a/solver/jobs.go b/solver/jobs.go
index 37df6fa9..0d59fb36 100644
--- a/solver/jobs.go
+++ b/solver/jobs.go
@@ -8,6 +8,7 @@ import (
 	"time"
 
 	"github.com/moby/buildkit/client"
+	"github.com/moby/buildkit/identity"
 	"github.com/moby/buildkit/session"
 	"github.com/moby/buildkit/solver/errdefs"
 	"github.com/moby/buildkit/util/flightcontrol"
@@ -417,7 +418,7 @@ func (jl *Solver) connectProgressFromState(target, src *state) {
 		if _, ok := target.allPw[j.pw]; !ok {
 			target.mpw.Add(j.pw)
 			target.allPw[j.pw] = struct{}{}
-			j.pw.Write(target.clientVertex.Digest.String(), target.clientVertex)
+			j.pw.Write(identity.NewID(), target.clientVertex)
 			if j.span != nil && j.span.SpanContext().IsValid() {
 				target.mspan.Add(j.span)
 			}
@@ -647,10 +648,10 @@ func (s *sharedOp) LoadCache(ctx context.Context, rec *CacheRecord) (Result, err
 	}
 	// no cache hit. start evaluating the node
 	span, ctx := tracing.StartSpan(ctx, "load cache: "+s.st.vtx.Name())
-	notifyStarted(ctx, &s.st.clientVertex, true, "load-cache")
+	notifyCompleted := notifyStarted(ctx, &s.st.clientVertex, true)
 	res, err := s.Cache().Load(withAncestorCacheOpts(ctx, s.st), rec)
 	tracing.FinishWithError(span, err)
-	notifyCompleted(ctx, &s.st.clientVertex, err, true, "load-cache")
+	notifyCompleted(err, true)
 	return res, err
 }
 
@@ -727,8 +728,8 @@ func (s *sharedOp) CalcSlowCache(ctx context.Context, index Index, p PreprocessF
 		if s.st.mspan.Span != nil {
 			ctx = trace.ContextWithSpan(ctx, s.st.mspan)
 		}
-		notifyStarted(ctx, &s.st.clientVertex, false, flightControlKey)
-		notifyCompleted(ctx, &s.st.clientVertex, err, false, flightControlKey)
+		notifyCompleted := notifyStarted(ctx, &s.st.clientVertex, false)
+		notifyCompleted(err, false)
 		return "", err
 	}
 	return key.(digest.Digest), nil
@@ -759,10 +760,10 @@ func (s *sharedOp) CacheMap(ctx context.Context, index int) (resp *cacheMapResp,
 		if len(s.st.vtx.Inputs()) == 0 {
 			// no cache hit. start evaluating the node
 			span, ctx := tracing.StartSpan(ctx, "cache request: "+s.st.vtx.Name())
-			notifyStarted(ctx, &s.st.clientVertex, false, flightControlKey)
+			notifyCompleted := notifyStarted(ctx, &s.st.clientVertex, false)
 			defer func() {
 				tracing.FinishWithError(span, retErr)
-				notifyCompleted(ctx, &s.st.clientVertex, retErr, false, flightControlKey)
+				notifyCompleted(retErr, false)
 			}()
 		}
 		res, done, err := op.CacheMap(ctx, s.st, len(s.cacheRes))
@@ -826,10 +827,10 @@ func (s *sharedOp) Exec(ctx context.Context, inputs []Result) (outputs []Result,
 
 		// no cache hit. start evaluating the node
 		span, ctx := tracing.StartSpan(ctx, s.st.vtx.Name())
-		notifyStarted(ctx, &s.st.clientVertex, false, flightControlKey)
+		notifyCompleted := notifyStarted(ctx, &s.st.clientVertex, false)
 		defer func() {
 			tracing.FinishWithError(span, retErr)
-			notifyCompleted(ctx, &s.st.clientVertex, retErr, false, flightControlKey)
+			notifyCompleted(retErr, false)
 		}()
 
 		res, err := op.Exec(ctx, s.st, inputs)
@@ -929,33 +930,26 @@ func (v *vertexWithCacheOptions) Inputs() []Edge {
 	return v.inputs
 }
 
-func notifyStarted(ctx context.Context, v *client.Vertex, cached bool, idSuffixes ...string) {
+func notifyStarted(ctx context.Context, v *client.Vertex, cached bool) func(err error, cached bool) {
 	pw, _, _ := progress.NewFromContext(ctx)
-	defer pw.Close()
-	now := time.Now()
-	v.Started = &now
+	start := time.Now()
+	v.Started = &start
 	v.Completed = nil
 	v.Cached = cached
-	id := v.Digest.String() + strings.Join(idSuffixes, "-")
+	id := identity.NewID()
 	pw.Write(id, *v)
-}
-
-func notifyCompleted(ctx context.Context, v *client.Vertex, err error, cached bool, idSuffixes ...string) {
-	pw, _, _ := progress.NewFromContext(ctx)
-	defer pw.Close()
-	now := time.Now()
-	if v.Started == nil {
-		v.Started = &now
+	return func(err error, cached bool) {
+		defer pw.Close()
+		stop := time.Now()
+		v.Completed = &stop
+		v.Cached = cached
+		if err != nil {
+			v.Error = err.Error()
+		} else {
+			v.Error = ""
+		}
+		pw.Write(id, *v)
 	}
-	v.Completed = &now
-	v.Cached = cached
-	if err != nil {
-		v.Error = err.Error()
-	} else {
-		v.Error = ""
-	}
-	id := v.Digest.String() + strings.Join(idSuffixes, "-")
-	pw.Write(id, *v)
 }
 
 type SlowCacheError struct {
diff --git a/solver/llbsolver/solver.go b/solver/llbsolver/solver.go
index 0a203f1f..7e2fb174 100644
--- a/solver/llbsolver/solver.go
+++ b/solver/llbsolver/solver.go
@@ -16,6 +16,7 @@ import (
 	"github.com/moby/buildkit/exporter/containerimage/exptypes"
 	"github.com/moby/buildkit/frontend"
 	"github.com/moby/buildkit/frontend/gateway"
+	"github.com/moby/buildkit/identity"
 	"github.com/moby/buildkit/session"
 	"github.com/moby/buildkit/solver"
 	"github.com/moby/buildkit/util/buildinfo"
@@ -431,37 +432,32 @@ func inBuilderContext(ctx context.Context, b solver.Builder, name, id string, f
 	}
 	return b.InContext(ctx, func(ctx context.Context, g session.Group) error {
 		pw, _, ctx := progress.NewFromContext(ctx, progress.WithMetadata("vertex", v.Digest))
-		notifyStarted(ctx, &v, false)
+		notifyCompleted := notifyStarted(ctx, &v, false)
 		defer pw.Close()
 		err := f(ctx, g)
-		notifyCompleted(ctx, &v, err, false)
+		notifyCompleted(err, false)
 		return err
 	})
 }
 
-func notifyStarted(ctx context.Context, v *client.Vertex, cached bool) {
+func notifyStarted(ctx context.Context, v *client.Vertex, cached bool) func(err error, cached bool) {
 	pw, _, _ := progress.NewFromContext(ctx)
-	defer pw.Close()
-	now := time.Now()
-	v.Started = &now
+	start := time.Now()
+	v.Started = &start
 	v.Completed = nil
 	v.Cached = cached
-	pw.Write(v.Digest.String(), *v)
-}
-
-func notifyCompleted(ctx context.Context, v *client.Vertex, err error, cached bool) {
-	pw, _, _ := progress.NewFromContext(ctx)
-	defer pw.Close()
-	now := time.Now()
-	if v.Started == nil {
-		v.Started = &now
+	id := identity.NewID()
+	pw.Write(id, *v)
+	return func(err error, cached bool) {
+		defer pw.Close()
+		stop := time.Now()
+		v.Completed = &stop
+		v.Cached = cached
+		if err != nil {
+			v.Error = err.Error()
+		}
+		pw.Write(id, *v)
 	}
-	v.Completed = &now
-	v.Cached = cached
-	if err != nil {
-		v.Error = err.Error()
-	}
-	pw.Write(v.Digest.String(), *v)
 }
 
 func supportedEntitlements(ents []string) []entitlements.Entitlement {
diff --git a/util/progress/controller/controller.go b/util/progress/controller/controller.go
index df9e4281..3d9693d4 100644
--- a/util/progress/controller/controller.go
+++ b/util/progress/controller/controller.go
@@ -6,6 +6,7 @@ import (
 	"time"
 
 	"github.com/moby/buildkit/client"
+	"github.com/moby/buildkit/identity"
 	"github.com/moby/buildkit/solver/pb"
 	"github.com/moby/buildkit/util/progress"
 	digest "github.com/opencontainers/go-digest"
@@ -16,6 +17,7 @@ type Controller struct {
 	started *time.Time
 	writer  progress.Writer
 	mu      sync.Mutex
+	id      string
 
 	Digest        digest.Digest
 	Name          string
@@ -34,10 +36,11 @@ func (c *Controller) Start(ctx context.Context) (context.Context, func(error)) {
 			now := time.Now()
 			c.started = &now
 			c.writer, _, _ = c.WriterFactory(ctx)
+			c.id = identity.NewID()
 		}
 
 		if c.Digest != "" {
-			c.writer.Write(c.Digest.String(), client.Vertex{
+			c.writer.Write(c.id, client.Vertex{
 				Digest:        c.Digest,
 				Name:          c.Name,
 				Started:       c.started,
@@ -56,7 +59,7 @@ func (c *Controller) Start(ctx context.Context) (context.Context, func(error)) {
 				errString = err.Error()
 			}
 			if c.Digest != "" {
-				c.writer.Write(c.Digest.String(), client.Vertex{
+				c.writer.Write(c.id, client.Vertex{
 					Digest:        c.Digest,
 					Name:          c.Name,
 					Started:       c.started,
@@ -67,6 +70,7 @@ func (c *Controller) Start(ctx context.Context) (context.Context, func(error)) {
 			}
 			c.writer.Close()
 			c.started = nil
+			c.id = ""
 		}
 	}
 }