diff --git a/tools/src/buildbucket/buildbucket.go b/tools/src/buildbucket/buildbucket.go
index 3ebcc1c1dbe..7e8a5321a88 100644
--- a/tools/src/buildbucket/buildbucket.go
+++ b/tools/src/buildbucket/buildbucket.go
@@ -201,6 +201,7 @@ func (r *Buildbucket) StartBuild(
 	ctx context.Context,
 	ps gerrit.Patchset,
 	builder Builder,
+	parentSwarmingRunId string,
 	forceBuild bool) (Build, error) {
 
 	id := ""
@@ -208,11 +209,16 @@ func (r *Buildbucket) StartBuild(
 		id = utils.Hash(ps, builder)
 	}
 
-	build, err := r.client.ScheduleBuild(ctx, &bbpb.ScheduleBuildRequest{
+	req := &bbpb.ScheduleBuildRequest{
 		RequestId:     id,
 		Builder:       builder.pb(),
 		GerritChanges: []*bbpb.GerritChange{gerritChange(ps)},
-	})
+	}
+	if parentSwarmingRunId != "" {
+		req.Swarming.ParentRunId = parentSwarmingRunId
+	}
+
+	build, err := r.client.ScheduleBuild(ctx, req)
 	if err != nil {
 		return Build{}, fmt.Errorf("failed to start build for patchset %+v on builder %+v: %w", ps, builder, err)
 	}
diff --git a/tools/src/cmd/cts/common/build.go b/tools/src/cmd/cts/common/build.go
index 99ce99d791a..a394213820d 100644
--- a/tools/src/cmd/cts/common/build.go
+++ b/tools/src/cmd/cts/common/build.go
@@ -117,6 +117,7 @@ func GetOrStartBuildsAndWait(
 	cfg Config,
 	ps gerrit.Patchset,
 	bb *buildbucket.Buildbucket,
+	parentSwarmingRunId string,
 	retest bool) (BuildsByName, error) {
 
 	builds := BuildsByName{}
@@ -151,7 +152,7 @@ func GetOrStartBuildsAndWait(
 	// Kick any missing builds
 	for name, builder := range cfg.Builders {
 		if build, found := builds[name]; !found || shouldKick(build) {
-			build, err := bb.StartBuild(ctx, ps, builder, retest)
+			build, err := bb.StartBuild(ctx, ps, builder, parentSwarmingRunId, retest)
 			if err != nil {
 				return nil, err
 			}
diff --git a/tools/src/cmd/cts/common/results.go b/tools/src/cmd/cts/common/results.go
index df471cadb2f..e4396bd0952 100644
--- a/tools/src/cmd/cts/common/results.go
+++ b/tools/src/cmd/cts/common/results.go
@@ -127,7 +127,7 @@ func (r *ResultSource) GetResults(ctx context.Context, cfg Config, auth auth.Opt
 	// Obtain the patchset's results, kicking a build if there are no results
 	// already available.
 	log.Printf("fetching results from cl %v ps %v...", ps.Change, ps.Patchset)
-	builds, err := GetOrStartBuildsAndWait(ctx, cfg, *ps, bb, false)
+	builds, err := GetOrStartBuildsAndWait(ctx, cfg, *ps, bb, "", false)
 	if err != nil {
 		return nil, err
 	}
diff --git a/tools/src/cmd/cts/roll/roll.go b/tools/src/cmd/cts/roll/roll.go
index b5523bd3e92..0737dc90358 100644
--- a/tools/src/cmd/cts/roll/roll.go
+++ b/tools/src/cmd/cts/roll/roll.go
@@ -68,15 +68,16 @@ const (
 )
 
 type rollerFlags struct {
-	gitPath        string
-	npmPath        string
-	nodePath       string
-	auth           authcli.Flags
-	cacheDir       string
-	force          bool // Create a new roll, even if CTS is up to date
-	rebuild        bool // Rebuild the expectations file from scratch
-	preserve       bool // If false, abandon past roll changes
-	sendToGardener bool // If true, automatically send to the gardener for review
+	gitPath             string
+	npmPath             string
+	nodePath            string
+	auth                authcli.Flags
+	cacheDir            string
+	force               bool // Create a new roll, even if CTS is up to date
+	rebuild             bool // Rebuild the expectations file from scratch
+	preserve            bool // If false, abandon past roll changes
+	sendToGardener      bool // If true, automatically send to the gardener for review
+	parentSwarmingRunId string
 }
 
 type cmd struct {
@@ -104,7 +105,7 @@ func (c *cmd) RegisterFlags(ctx context.Context, cfg common.Config) ([]string, e
 	flag.BoolVar(&c.flags.rebuild, "rebuild", false, "rebuild the expectation file from scratch")
 	flag.BoolVar(&c.flags.preserve, "preserve", false, "do not abandon existing rolls")
 	flag.BoolVar(&c.flags.sendToGardener, "send-to-gardener", false, "send the CL to the WebGPU gardener for review")
-
+	flag.StringVar(&c.flags.parentSwarmingRunId, "parent-swarming-run-id", "", "parent swarming run id. All triggered tasks will be children of this task and will be canceled if the parent is canceled.")
 	return nil, nil
 }
 
@@ -164,31 +165,33 @@ func (c *cmd) Run(ctx context.Context, cfg common.Config) error {
 
 	// Construct the roller, and roll
 	r := roller{
-		cfg:      cfg,
-		flags:    c.flags,
-		auth:     auth,
-		bb:       bb,
-		rdb:      rdb,
-		git:      git,
-		gerrit:   gerrit,
-		chromium: chromium,
-		dawn:     dawn,
-		ctsDir:   ctsDir,
+		cfg:                 cfg,
+		flags:               c.flags,
+		auth:                auth,
+		bb:                  bb,
+		parentSwarmingRunId: c.flags.parentSwarmingRunId,
+		rdb:                 rdb,
+		git:                 git,
+		gerrit:              gerrit,
+		chromium:            chromium,
+		dawn:                dawn,
+		ctsDir:              ctsDir,
 	}
 	return r.roll(ctx)
 }
 
 type roller struct {
-	cfg      common.Config
-	flags    rollerFlags
-	auth     auth.Options
-	bb       *buildbucket.Buildbucket
-	rdb      *resultsdb.ResultsDB
-	git      *git.Git
-	gerrit   *gerrit.Gerrit
-	chromium *gitiles.Gitiles
-	dawn     *gitiles.Gitiles
-	ctsDir   string
+	cfg                 common.Config
+	flags               rollerFlags
+	auth                auth.Options
+	bb                  *buildbucket.Buildbucket
+	parentSwarmingRunId string
+	rdb                 *resultsdb.ResultsDB
+	git                 *git.Git
+	gerrit              *gerrit.Gerrit
+	chromium            *gitiles.Gitiles
+	dawn                *gitiles.Gitiles
+	ctsDir              string
 }
 
 func (r *roller) roll(ctx context.Context) error {
@@ -335,7 +338,7 @@ func (r *roller) roll(ctx context.Context) error {
 	for attempt := 0; ; attempt++ {
 		// Kick builds
 		log.Printf("building (attempt %v)...\n", attempt)
-		builds, err := common.GetOrStartBuildsAndWait(ctx, r.cfg, ps, r.bb, false)
+		builds, err := common.GetOrStartBuildsAndWait(ctx, r.cfg, ps, r.bb, r.parentSwarmingRunId, false)
 		if err != nil {
 			return err
 		}