Trim flame graph nodes relative to node's parent

gen/proto/swagger/parca/query/v1alpha1/query.swagger.json

@@ -988,7 +988,7 @@
         "trimmed": {
           "type": "string",
           "format": "int64",
-          "description": "trimmed is the amount of samples trimmed from the flame graph."
+          "description": "trimmed is the amount of cumulative value trimmed from the flame graph."
         }
       },
       "title": "Flamegraph is the flame graph report type"

gen/proto/swagger/parca/share/v1alpha1/share.swagger.json

@@ -430,7 +430,7 @@
         "trimmed": {
           "type": "string",
           "format": "int64",
-          "description": "trimmed is the amount of samples trimmed from the flame graph."
+          "description": "trimmed is the amount of cumulative value trimmed from the flame graph."
         }
       },
       "title": "Flamegraph is the flame graph report type"

pkg/query/flamegraph_table.go

@@ -501,34 +501,33 @@ func (n FlamegraphChildren) Diff() int64 {
 	return diff
 }
 
-func TrimFlamegraph(ctx context.Context, tracer trace.Tracer, graph *querypb.Flamegraph, thresholdRate float32) *querypb.Flamegraph {
+func TrimFlamegraph(ctx context.Context, tracer trace.Tracer, graph *querypb.Flamegraph, threshold float32) *querypb.Flamegraph {
 	ctx, span := tracer.Start(ctx, "trimFlamegraph")
 	defer span.End()
 	if graph == nil {
 		return nil
 	}
-	//nolint:staticcheck // SA1019: TODO: The total should be passed differently in the future.
-	threshold := int64(float64(thresholdRate) * float64(graph.Total))
-	var children FlamegraphChildren = trimFlamegraphNodes(ctx, tracer, graph.Root.Children, threshold)
-	newTotal := int64(0)
-	newDiff := int64(0)
-	if len(graph.Root.Children) > 0 {
-		newTotal = children.Cumulative()
-		newDiff = children.Diff()
-	}
+
+	children, trimmedCumulative := trimFlamegraphNodes(
+		ctx,
+		tracer,
+		graph.Root.Children,
+		graph.Root.Cumulative,
+		threshold,
+	)
 
 	trimmedGraph := &querypb.Flamegraph{
 		Root: &querypb.FlamegraphRootNode{
 			Children:   children,
-			Cumulative: newTotal,
-			Diff:       newDiff,
+			Cumulative: graph.Root.Cumulative,
+			Diff:       graph.Root.Diff,
 		},
 		//nolint:staticcheck // SA1019: Fow now we want to support these APIs
-		Total: newTotal,
+		Total: graph.Total,
 		//nolint:staticcheck // SA1019: Fow now we want to support these APIs
 		UntrimmedTotal: graph.Total,
 		//nolint:staticcheck // SA1019: Fow now we want to support these APIs
-		Trimmed:     graph.Total - newTotal,
+		Trimmed:     trimmedCumulative,
 		Unit:        graph.Unit,
 		Height:      graph.Height,
 		StringTable: graph.StringTable,
@@ -540,27 +539,37 @@ func TrimFlamegraph(ctx context.Context, tracer trace.Tracer, graph *querypb.Fla
 	return trimmedGraph
 }
 
-func trimFlamegraphNodes(ctx context.Context, tracer trace.Tracer, nodes []*querypb.FlamegraphNode, threshold int64) []*querypb.FlamegraphNode {
-	var trimmedNodes []*querypb.FlamegraphNode
+func trimFlamegraphNodes(ctx context.Context, tracer trace.Tracer, nodes []*querypb.FlamegraphNode, parentCumulative int64, threshold float32) ([]*querypb.FlamegraphNode, int64) {
+	var (
+		trimmedCumulative int64
+		remainingNodes    []*querypb.FlamegraphNode
+	)
 	for _, node := range nodes {
-		if node.Cumulative < threshold {
+		c := float32(node.Cumulative)
+		ct := float32(parentCumulative) * (threshold)
+		// If the node's cumulative value is less than the (threshold * (cumulative value)) of this level, skip it.
+		if c < ct {
+			trimmedCumulative += node.Cumulative
 			continue
 		}
-		var oldChildren FlamegraphChildren = node.Children
-		flat := node.Cumulative - oldChildren.Cumulative()
-		var children FlamegraphChildren = trimFlamegraphNodes(ctx, tracer, node.Children, threshold)
-		newCum := flat
-		newDiff := node.Diff
-		if len(children) > 0 {
-			newCum += children.Cumulative()
-			newDiff += children.Diff()
+		// We have reached a leaf node.
+		if node.Children == nil {
+			remainingNodes = append(remainingNodes, node)
+			continue
 		}
-		trimmedNodes = append(trimmedNodes, &querypb.FlamegraphNode{
-			Meta:       node.Meta,
-			Cumulative: newCum,
-			Diff:       newDiff,
-			Children:   children,
-		})
+
+		children, childrenTrimmedCumulative := trimFlamegraphNodes(
+			ctx,
+			tracer,
+			node.Children,
+			node.Cumulative,
+			threshold,
+		)
+
+		trimmedCumulative += childrenTrimmedCumulative
+		node.Children = children
+		remainingNodes = append(remainingNodes, node)
 	}
-	return trimmedNodes
+
+	return remainingNodes, trimmedCumulative
 }

pkg/query/flamegraph_table_test.go

@@ -729,7 +729,10 @@ func TestFlamegraphTrimming(t *testing.T) {
 						LineIndex:     0,
 					},
 					Children: []*pb.FlamegraphNode{
-						{Cumulative: 1},
+						{
+							// This node is trimmed because it is below the threshold.
+							Cumulative: 1,
+						},
 						{
 							Cumulative: 30,
 							Meta: &pb.FlamegraphNodeMeta{
@@ -761,7 +764,8 @@ func TestFlamegraphTrimming(t *testing.T) {
 					},
 				},
 				{
-					Cumulative: 1,
+					// This node is trimmed because it is below the threshold.
+					Cumulative: 3,
 					Meta: &pb.FlamegraphNodeMeta{
 						LocationIndex: 3,
 						LineIndex:     0,
@@ -770,16 +774,17 @@ func TestFlamegraphTrimming(t *testing.T) {
 			},
 		},
 	}
-	trimmedGraph := TrimFlamegraph(context.Background(), trace.NewNoopTracerProvider().Tracer(""), fullGraph, 0.02)
+	// trim all children that have less than 10% cumulative value of the parent.
+	trimmedGraph := TrimFlamegraph(context.Background(), trace.NewNoopTracerProvider().Tracer(""), fullGraph, 0.1)
 	require.Equal(t, &pb.Flamegraph{
-		Total:          100,
-		Trimmed:        2,
+		Total:          102,
+		Trimmed:        4,
 		UntrimmedTotal: 102,
 		Root: &pb.FlamegraphRootNode{
-			Cumulative: 100,
+			Cumulative: 102,
 			Children: []*pb.FlamegraphNode{
 				{
-					Cumulative: 100,
+					Cumulative: 101,
 					Meta: &pb.FlamegraphNodeMeta{
 						LocationIndex: 1,
 						LineIndex:     0,
@@ -861,13 +866,13 @@ func TestFlamegraphTrimmingNodeWithFlatValues(t *testing.T) {
 	}
 	trimmedGraph := TrimFlamegraph(context.Background(), trace.NewNoopTracerProvider().Tracer(""), fullGraph, float32(0.02))
 	require.Equal(t, &pb.Flamegraph{
-		Total:          150,
+		Total:          151,
 		UntrimmedTotal: 151,
 		Trimmed:        1,
 		Root: &pb.FlamegraphRootNode{
-			Cumulative: 150,
+			Cumulative: 151,
 			Children: []*pb.FlamegraphNode{{
-				Cumulative: 150,
+				Cumulative: 151,
 				Children: []*pb.FlamegraphNode{{
 					Cumulative: 100,
 				}},
@@ -1009,11 +1014,12 @@ func TestFlamegraphTrimmingAndFiltering(t *testing.T) {
 
 	require.Equal(t, int32(6), fg.Height)
 
-	// The raw flamegraph had 12+3+3 = 18 samples.
+	// The unfiltered flamegraph had 15+3 = 18 samples.
+	// There were nodes that got trimmed with a cumulative value of 3.
 	require.Equal(t, int64(3), filtered)
 	require.Equal(t, int64(3), fg.Trimmed)
 	//nolint:staticcheck // SA1019: Fow now we want to support these APIs
-	require.Equal(t, int64(12), fg.Total)
+	require.Equal(t, int64(15), fg.Total)
 
 	// Check if tables and thus deduplication was correct and deterministic
 
@@ -1042,18 +1048,18 @@ func TestFlamegraphTrimmingAndFiltering(t *testing.T) {
 	// Check the recursive flamegraph that references the tables above.
 
 	expected := &pb.FlamegraphRootNode{
-		Cumulative: 12,
+		Cumulative: 15,
 		Children: []*pb.FlamegraphNode{{
-			Cumulative: 12,
+			Cumulative: 15,
 			Meta:       &pb.FlamegraphNodeMeta{LocationIndex: 1},
 			Children: []*pb.FlamegraphNode{{
-				Cumulative: 12,
+				Cumulative: 15,
 				Meta:       &pb.FlamegraphNodeMeta{LocationIndex: 2},
 				Children: []*pb.FlamegraphNode{{
-					Cumulative: 12,
+					Cumulative: 15,
 					Meta:       &pb.FlamegraphNodeMeta{LocationIndex: 3},
 					Children: []*pb.FlamegraphNode{{
-						Cumulative: 12,
+						Cumulative: 15,
 						Meta:       &pb.FlamegraphNodeMeta{LocationIndex: 4},
 					}},
 				}},

proto/parca/query/v1alpha1/query.proto

@@ -316,7 +316,7 @@ message Flamegraph {
   // Use trimmed instead.
   int64 untrimmed_total = 9 [deprecated = true];
 
-  // trimmed is the amount of samples trimmed from the flame graph.
+  // trimmed is the amount of cumulative value trimmed from the flame graph.
   int64 trimmed = 10;
 }
 

ui/packages/shared/client/src/parca/query/v1alpha1/query.ts

@@ -595,7 +595,7 @@ export interface Flamegraph {
      */
     untrimmedTotal: string;
     /**
-     * trimmed is the amount of samples trimmed from the flame graph.
+     * trimmed is the amount of cumulative value trimmed from the flame graph.
      *
      * @generated from protobuf field: int64 trimmed = 10;
      */

ui/packages/shared/profile/src/ProfileIcicleGraph/index.tsx

@@ -69,7 +69,6 @@ const ProfileIcicleGraph = ({
     trimmedFormatted,
     trimmedPercentage,
     isFiltered,
-    filteredFormatted,
     filteredPercentage,
   ] = useMemo(() => {
     if (graph === undefined) {
@@ -90,8 +89,7 @@ const ProfileIcicleGraph = ({
       numberFormatter.format(trimmed),
       numberFormatter.format((trimmed * BigInt(100)) / rawTotalDivisor),
       filtered > 0,
-      numberFormatter.format(filtered),
-      numberFormatter.format((filtered * BigInt(100)) / rawTotalDivisor),
+      numberFormatter.format((total * BigInt(100)) / rawTotalDivisor),
     ];
   }, [filtered, graph, total]);
 
@@ -118,6 +116,10 @@ const ProfileIcicleGraph = ({
 
   if (total === BigInt(0) && !loading) return <>Profile has no samples</>;
 
+  if (isTrimmed) {
+    console.info(`Trimmed ${trimmedFormatted} (${trimmedPercentage}%) too small values.`);
+  }
+
   return (
     <div className="relative">
       {compareMode && <DiffLegend />}
@@ -132,22 +134,15 @@ const ProfileIcicleGraph = ({
         />
       </div>
       <p className="my-2 text-xs">
-        Showing {totalFormatted} {isFiltered || isTrimmed ? <span>of {rawFormatted} </span> : <></>}
-        samples.{' '}
+        Showing {totalFormatted}{' '}
         {isFiltered ? (
           <span>
-            Filtered {filteredFormatted} ({filteredPercentage}%) samples.&nbsp;
-          </span>
-        ) : (
-          <></>
-        )}
-        {isTrimmed ? (
-          <span>
-            Trimmed {trimmedFormatted} ({trimmedPercentage}%) too small samples.
+            ({filteredPercentage}%) filtered of {rawFormatted}{' '}
           </span>
         ) : (
           <></>
         )}
+        values.{' '}
       </p>
     </div>
   );