diff --git a/render/container.go b/render/container.go
index 347d56745..39b9e52b3 100644
--- a/render/container.go
+++ b/render/container.go
@@ -275,7 +275,7 @@ func (m containerImageRenderer) Render(ctx context.Context, rpt report.Report) N
 		id := report.MakeContainerImageNodeID(imageID)
 		ret.addChildAndChildren(n, id, report.ContainerImage)
 	}
-	return ret.result(containers)
+	return ret.result(ctx, containers)
 }
 
 func containerImageNodeID(n report.Node) string {
@@ -328,5 +328,5 @@ func (m containerHostnameRenderer) Render(ctx context.Context, rpt report.Report
 		}
 		ret.addChildAndChildren(n, id, containerHostnameTopology)
 	}
-	return ret.result(containers)
+	return ret.result(ctx, containers)
 }
diff --git a/render/endpoint.go b/render/endpoint.go
index c645bb995..ab57180d4 100644
--- a/render/endpoint.go
+++ b/render/endpoint.go
@@ -47,5 +47,5 @@ func (e mapEndpoints) Render(ctx context.Context, rpt report.Report) Nodes {
 			ret.addChild(n, id, e.topology)
 		}
 	}
-	return ret.result(endpoints)
+	return ret.result(ctx, endpoints)
 }
diff --git a/render/filters.go b/render/filters.go
index 0daa6fbe7..4144ace4c 100644
--- a/render/filters.go
+++ b/render/filters.go
@@ -17,7 +17,7 @@ const (
 // in one call - useful for functions that need to consider the entire graph.
 // We should minimise the use of this renderer type, as it is very inflexible.
 type CustomRenderer struct {
-	RenderFunc func(Nodes) Nodes
+	RenderFunc func(context.Context, Nodes) Nodes
 	Renderer
 }
 
@@ -26,7 +26,7 @@ func (c CustomRenderer) Render(ctx context.Context, rpt report.Report) Nodes {
 	if ctx.Err() != nil {
 		return Nodes{}
 	}
-	return c.RenderFunc(c.Renderer.Render(ctx, rpt))
+	return c.RenderFunc(ctx, c.Renderer.Render(ctx, rpt))
 }
 
 // FilterFunc is the function type used by Filters
@@ -189,7 +189,7 @@ func filterInternetAdjacencies(nodes report.Nodes) {
 func ColorConnected(r Renderer) Renderer {
 	return CustomRenderer{
 		Renderer: r,
-		RenderFunc: func(input Nodes) Nodes {
+		RenderFunc: func(ctx context.Context, input Nodes) Nodes {
 			output := input.Copy()
 			for id := range connected(input.Nodes) {
 				output[id] = output[id].WithLatest(IsConnectedMark, mtime.Now(), "true")
diff --git a/render/host.go b/render/host.go
index 26a4c5cc7..742dc9b3e 100644
--- a/render/host.go
+++ b/render/host.go
@@ -1,6 +1,8 @@
 package render
 
 import (
+	"context"
+
 	"github.com/weaveworks/scope/report"
 )
 
@@ -25,7 +27,7 @@ var HostRenderer = MakeReduce(
 // format for a host, but without any Major or Minor labels.  It does
 // not have enough info to do that, and the resulting graph must be
 // merged with a host graph to get that info.
-func nodes2Hosts(nodes Nodes) Nodes {
+func nodes2Hosts(ctx context.Context, nodes Nodes) Nodes {
 	ret := newJoinResults(nil)
 
 	for _, n := range nodes.Nodes {
@@ -47,7 +49,7 @@ func nodes2Hosts(nodes Nodes) Nodes {
 			}
 		}
 	}
-	return ret.result(nodes)
+	return ret.result(ctx, nodes)
 }
 
 func endpoint2Host(n report.Node) string {
diff --git a/render/pod.go b/render/pod.go
index 2b5beb9e2..321c588ad 100644
--- a/render/pod.go
+++ b/render/pod.go
@@ -197,5 +197,5 @@ func (m Map2Parent) Render(ctx context.Context, rpt report.Report) Nodes {
 			ret.addChildAndChildren(n, id, Pseudo)
 		}
 	}
-	return ret.result(input)
+	return ret.result(ctx, input)
 }
diff --git a/render/process.go b/render/process.go
index 2cce7dc0d..4b5c1c7d9 100644
--- a/render/process.go
+++ b/render/process.go
@@ -95,7 +95,7 @@ func hasMoreThanOneConnection(n report.Node, endpoints report.Nodes) bool {
 var processNameTopology = MakeGroupNodeTopology(report.Process, report.Name)
 
 // processes2Names maps process Nodes to Nodes for each process name.
-func processes2Names(processes Nodes) Nodes {
+func processes2Names(ctx context.Context, processes Nodes) Nodes {
 	ret := newJoinResults(nil)
 
 	for _, n := range processes.Nodes {
@@ -105,5 +105,5 @@ func processes2Names(processes Nodes) Nodes {
 			ret.addChildAndChildren(n, name, processNameTopology)
 		}
 	}
-	return ret.result(processes)
+	return ret.result(ctx, processes)
 }
diff --git a/render/render.go b/render/render.go
index efeea1fdd..025e86c10 100644
--- a/render/render.go
+++ b/render/render.go
@@ -133,7 +133,7 @@ func (m Map) Render(ctx context.Context, rpt report.Report) Nodes {
 	span.LogFields(otlog.Int("input.nodes", len(input.Nodes)),
 		otlog.Int("ouput.nodes", len(output.nodes)))
 
-	return output.result(input)
+	return output.result(ctx, input)
 }
 
 // Condition is a predecate over the entire report that can evaluate to true or false.
@@ -233,8 +233,11 @@ func (ret *joinResults) passThrough(n report.Node) {
 
 // Rewrite Adjacency of nodes in ret mapped from original nodes in
 // input, and return the result.
-func (ret *joinResults) result(input Nodes) Nodes {
+func (ret *joinResults) result(ctx context.Context, input Nodes) Nodes {
 	for _, n := range input.Nodes {
+		if ctx.Err() != nil { // check if cancelled
+			return Nodes{}
+		}
 		outID, ok := ret.mapped[n.ID]
 		if !ok {
 			continue