ui/src/plugins/dev.perfetto.ProcessSummary/group_summary_track.ts - third_party/perfetto - Git at Google

 // Copyright (C) 2025 The Android Open Source Project
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //      http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 import {BigintMath as BIMath} from '../../base/bigint_math';
 import {Monitor} from '../../base/monitor';
 import {searchEq, searchRange} from '../../base/binary_search';
 import {assertExists, assertTrue} from '../../base/logging';
 import {duration, time, Time} from '../../base/time';
 import m from 'mithril';
 import {colorForThread, colorForTid} from '../../components/colorizer';
 import {TrackData} from '../../components/tracks/track_data';
 import {TimelineFetcher} from '../../components/tracks/track_helper';
 import {checkerboardExcept} from '../../components/checkerboard';
 import {TrackRenderer} from '../../public/track';
 import {LONG, NUM, QueryResult} from '../../trace_processor/query_result';
 import {uuidv4Sql} from '../../base/uuid';
 import {
   TrackContext,
   TrackMouseEvent,
   TrackRenderContext,
 } from '../../public/track';
 import {Point2D} from '../../base/geom';
 import {TimeScale} from '../../base/time_scale';
 import {Trace} from '../../public/trace';
 import {ThreadMap} from '../dev.perfetto.Thread/threads';
 import {AsyncDisposableStack} from '../../base/disposable_stack';
 import {
   createPerfettoTable,
   createVirtualTable,
 } from '../../trace_processor/sql_utils';
 import {Dataset} from '../../trace_processor/dataset';
 import {TrackNode} from '../../public/workspace';

 export const SLICE_TRACK_SUMMARY_KIND = 'SliceTrackSummary';

 const MARGIN_TOP = 5;
 const RECT_HEIGHT = 30;
 const TRACK_HEIGHT = MARGIN_TOP * 2 + RECT_HEIGHT;

 interface Data extends TrackData {
   maxLanes: number;

   // Slices are stored in a columnar fashion. All fields have the same length.
   counts: Uint32Array;
   starts: BigInt64Array;
   ends: BigInt64Array;
   utids: Int32Array;
   lanes: Uint32Array;
 }

 export interface Config {
   pidForColor: bigint | number;
   upid: number | null;
   utid: number | null;
 }

 type Mode = 'sched' | 'slices';

 interface GroupSummaryHover {
   utid: number;
   lane: number;
   count: number;
   pid?: bigint;
 }

 function computeHover(
   pos: Point2D | undefined,
   timescale: TimeScale,
   data: Data,
   threads: ThreadMap,
 ): GroupSummaryHover | undefined {
   if (pos === undefined) return undefined;

   const {x, y} = pos;
   if (y < MARGIN_TOP || y > MARGIN_TOP + RECT_HEIGHT) return undefined;

   const laneHeight = Math.floor(RECT_HEIGHT / data.maxLanes);
   const lane = Math.floor((y - MARGIN_TOP) / (laneHeight + 1));
   const t = timescale.pxToHpTime(x).toTime('floor');

   const [i, j] = searchRange(data.starts, t, searchEq(data.lanes, lane));
   if (i === j || i >= data.starts.length || t > data.ends[i]) return undefined;

   const utid = data.utids[i];
   const count = data.counts[i];
   const pid = threads.get(utid)?.pid;
   return {utid, lane, count, pid};
 }

 export class GroupSummaryTrack implements TrackRenderer {
   private hover?: GroupSummaryHover;
   private fetcher = new TimelineFetcher(this.onBoundsChange.bind(this));
   private trackUuid = uuidv4Sql();
   private mode: Mode = 'slices';
   private maxLanes: number = 1;
   private sliceTracks: Array<{uri: string; dataset: Dataset}> = [];

   // Monitor for local hover state (triggers DOM redraw for tooltip).
   private readonly hoverMonitor = new Monitor([
     () => this.hover?.utid,
     () => this.hover?.lane,
     () => this.hover?.count,
   ]);

   constructor(
     private readonly trace: Trace,
     private readonly config: Config,
     private readonly cpuCount: number,
     private readonly threads: ThreadMap,
     hasSched: boolean,
   ) {
     this.mode = hasSched ? 'sched' : 'slices';
   }

   async onCreate(ctx: TrackContext): Promise<void> {
     if (this.mode === 'sched') {
       await this.createSchedMipmap();
     } else {
       await this.createSlicesMipmap(ctx.trackNode);
     }
   }

   private async createSchedMipmap(): Promise<void> {
     const getQuery = () => {
       if (this.config.upid !== null) {
         return `
           select
             s.id,
             s.ts,
             s.dur,
             c.cpu,
             s.utid
           from thread t
           cross join sched s using (utid)
           cross join cpu c using (ucpu)
           where
             t.is_idle = 0 and
             t.upid = ${this.config.upid}
           order by ts
         `;
       }
       assertExists(this.config.utid);
       return `
         select
           s.id,
           s.ts,
           s.dur,
           c.cpu,
           s.utid
         from sched s
         cross join cpu c using (ucpu)
         where
           s.utid = ${this.config.utid}
       `;
     };

     const trash = new AsyncDisposableStack();
     trash.use(
       await createPerfettoTable({
         engine: this.trace.engine,
         name: `tmp_${this.trackUuid}`,
         as: getQuery(),
       }),
     );
     await createVirtualTable({
       engine: this.trace.engine,
       name: `process_summary_${this.trackUuid}`,
       using: `__intrinsic_slice_mipmap((
         select
           s.id,
           s.ts,
           iif(
             s.dur = -1,
             ifnull(
               (
                 select n.ts
                 from tmp_${this.trackUuid} n
                 where n.ts > s.ts and n.cpu = s.cpu
                 order by ts
                 limit 1
               ),
               trace_end()
             ) - s.ts,
             s.dur
           ) as dur,
           s.cpu as depth
         from tmp_${this.trackUuid} s
       ))`,
     });
     await trash.asyncDispose();

     this.maxLanes = this.cpuCount;
   }

   private fetchDatasetsFromSliceTracks(node: TrackNode) {
     assertTrue(
       this.mode === 'slices',
       'Can only collect slice tracks in slice mode',
     );
     const stack: TrackNode[] = [node];
     while (stack.length > 0 && this.sliceTracks.length < 8) {
       const node = stack.pop()!;

       // Try to get track and dataset
       const track =
         node.uri !== undefined
           ? this.trace.tracks.getTrack(node.uri)
           : undefined;
       const dataset = track?.renderer.getDataset?.();

       // Check if it's a valid slice track WITH depth column
       const sliceSchema = {ts: LONG, dur: LONG, depth: NUM};
       const isValidSliceTrack = dataset?.implements(sliceSchema) ?? false;

       if (isValidSliceTrack && dataset !== undefined) {
         // Add track - we'll filter to depth = 0 in SQL
         this.sliceTracks.push({
           uri: node.uri!,
           dataset: dataset,
         });
       } else {
         // Not valid - traverse children
         for (let i = node.children.length - 1; i >= 0; i--) {
           stack.push(node.children[i]);
         }
       }
     }
   }

   private async createSlicesMipmap(node: TrackNode): Promise<void> {
     // Fetch datasets from child tracks
     this.fetchDatasetsFromSliceTracks(node);

     if (this.sliceTracks.length === 0) {
       // No valid slice tracks found - create empty table
       await createVirtualTable({
         engine: this.trace.engine,
         name: `process_summary_${this.trackUuid}`,
         using: `__intrinsic_slice_mipmap((
           select
             cast(0 as int) as id,
             cast(0 as bigint) as ts,
             cast(0 as bigint) as dur,
             cast(0 as int) as depth
           where 0
         ))`,
       });
       this.maxLanes = 1;
       return;
     }

     // Create union of all slice tracks with track index as depth
     const unions = this.sliceTracks
       .map(({dataset}, idx) => {
         return `
         select
           id,
           ts,
           iif(dur = -1, trace_end() - ts, dur) as dur,
           ${idx} as depth
         from (${dataset.query()})
         where depth = 0
       `;
       })
       .join(' union all ');

     await createVirtualTable({
       engine: this.trace.engine,
       name: `process_summary_${this.trackUuid}`,
       using: `__intrinsic_slice_mipmap((
         ${unions}
       ))`,
     });
     this.maxLanes = 8;
   }

   async onUpdate({
     visibleWindow,
     resolution,
   }: TrackRenderContext): Promise<void> {
     await this.fetcher.requestData(visibleWindow.toTimeSpan(), resolution);
   }

   async onDestroy(): Promise<void> {
     this.fetcher[Symbol.dispose]();
     await this.trace.engine.tryQuery(`
       drop table process_summary_${this.trackUuid}
     `);
   }

   async onBoundsChange(
     start: time,
     end: time,
     resolution: duration,
   ): Promise<Data> {
     // Resolution must always be a power of 2 for this logic to work
     assertTrue(BIMath.popcount(resolution) === 1, `${resolution} not pow of 2`);

     const queryRes = await this.queryData(start, end, resolution);
     const numRows = queryRes.numRows();
     const slices: Data = {
       start,
       end,
       resolution,
       length: numRows,
       maxLanes: this.maxLanes,
       counts: new Uint32Array(numRows),
       starts: new BigInt64Array(numRows),
       ends: new BigInt64Array(numRows),
       lanes: new Uint32Array(numRows),
       utids: new Int32Array(numRows),
     };

     const it = queryRes.iter({
       count: NUM,
       ts: LONG,
       dur: LONG,
       lane: NUM,
       utid: NUM,
     });

     for (let row = 0; it.valid(); it.next(), row++) {
       const start = Time.fromRaw(it.ts);
       const dur = it.dur;
       const end = Time.add(start, dur);

       slices.counts[row] = it.count;
       slices.starts[row] = start;
       slices.ends[row] = end;
       slices.lanes[row] = it.lane;
       slices.utids[row] = it.utid;
       slices.end = Time.max(end, slices.end);
     }
     return slices;
   }

   private async queryData(
     start: time,
     end: time,
     bucketSize: duration,
   ): Promise<QueryResult> {
     if (this.mode === 'sched') {
       return this.trace.engine.query(`
         select
           (z.ts / ${bucketSize}) * ${bucketSize} as ts,
           iif(s.dur = -1, s.dur, max(z.dur, ${bucketSize})) as dur,
           z.count,
           z.depth as lane,
           s.utid
         from process_summary_${this.trackUuid}(
           ${start}, ${end}, ${bucketSize}
         ) z
         cross join sched s using (id)
       `);
     } else {
       return this.trace.engine.query(`
         select
           (z.ts / ${bucketSize}) * ${bucketSize} as ts,
           max(z.dur, ${bucketSize}) as dur,
           z.count,
           z.depth as lane,
           -1 as utid
         from process_summary_${this.trackUuid}(
           ${start}, ${end}, ${bucketSize}
         ) z
       `);
     }
   }

   getHeight(): number {
     return TRACK_HEIGHT;
   }

   renderTooltip(): m.Children {
     if (this.hover === undefined) {
       return undefined;
     }

     if (this.mode === 'sched') {
       // Show thread/process info for scheduling mode
       const hoveredThread = this.threads.get(this.hover.utid);
       if (!hoveredThread) {
         return undefined;
       }

       const tidText = `T: ${hoveredThread.threadName} [${hoveredThread.tid}]`;

       const count = this.hover.count;
       const countDiv = count > 1 && m('div', `and ${count - 1} other events`);
       if (hoveredThread.pid !== undefined) {
         const pidText = `P: ${hoveredThread.procName} [${hoveredThread.pid}]`;
         return m('.tooltip', [m('div', pidText), m('div', tidText), countDiv]);
       } else {
         return m('.tooltip', tidText, countDiv);
       }
     } else {
       // Show track name/info for slice mode
       const laneIndex = this.hover.lane;
       if (laneIndex < 0 || laneIndex >= this.sliceTracks.length) {
         return undefined;
       }

       const trackUri = this.sliceTracks[laneIndex].uri;
       const track = this.trace.tracks.getTrack(trackUri);
       const trackTitle = (track as {title?: string})?.title ?? trackUri;

       const count = this.hover.count;
       const countDiv = count > 1 && m('div', `${count} slices`);

       return m('.tooltip', [m('div', `Track: ${trackTitle}`), countDiv]);
     }
   }

   render({ctx, size, timescale, visibleWindow}: TrackRenderContext): void {
     const data = this.fetcher.data;

     if (data === undefined) return; // Can't possibly draw anything.

     // If the cached trace slices don't fully cover the visible time range,
     // show a gray rectangle with a "Loading..." label.
     checkerboardExcept(
       ctx,
       this.getHeight(),
       0,
       size.width,
       timescale.timeToPx(data.start),
       timescale.timeToPx(data.end),
     );

     assertTrue(data.starts.length === data.ends.length);
     assertTrue(data.starts.length === data.utids.length);

     const laneHeight = Math.floor(RECT_HEIGHT / data.maxLanes);

     for (let i = 0; i < data.ends.length; i++) {
       const tStart = Time.fromRaw(data.starts[i]);
       const tEnd = Time.fromRaw(data.ends[i]);

       // Cull slices that lie completely outside the visible window
       if (!visibleWindow.overlaps(tStart, tEnd)) continue;

       const utid = data.utids[i];
       const lane = data.lanes[i];

       const rectStart = Math.floor(timescale.timeToPx(tStart));
       const rectEnd = Math.floor(timescale.timeToPx(tEnd));
       const rectWidth = Math.max(1, rectEnd - rectStart);

       let colorScheme;

       if (this.mode === 'sched') {
         // Scheduling mode: color by thread (utid)
         const threadInfo = this.threads.get(utid);
         // eslint-disable-next-line @typescript-eslint/strict-boolean-expressions
         const pid = (threadInfo ? threadInfo.pid : -1) || -1;

         const isHovering = this.trace.timeline.hoveredUtid !== undefined;
         const isThreadHovered = this.trace.timeline.hoveredUtid === utid;
         const isProcessHovered = this.trace.timeline.hoveredPid === pid;
         colorScheme = colorForThread(threadInfo);

         if (isHovering && !isThreadHovered) {
           if (!isProcessHovered) {
             ctx.fillStyle = colorScheme.disabled.cssString;
           } else {
             ctx.fillStyle = colorScheme.variant.cssString;
           }
         } else {
           ctx.fillStyle = colorScheme.base.cssString;
         }
       } else {
         // Slice mode: consistent color based on pidForColor
         colorScheme = colorForTid(this.config.pidForColor);
         ctx.fillStyle = colorScheme.base.cssString;
       }

       const y = MARGIN_TOP + laneHeight * lane + lane;
       ctx.fillRect(rectStart, y, rectWidth, laneHeight);
     }
   }

   onMouseMove({x, y, timescale}: TrackMouseEvent) {
     const data = this.fetcher.data;
     if (data === undefined) return;
     this.hover = computeHover({x, y}, timescale, data, this.threads);
     if (this.hoverMonitor.ifStateChanged()) {
       if (this.mode === 'sched') {
         this.trace.timeline.hoveredUtid = this.hover?.utid;
         this.trace.timeline.hoveredPid = this.hover?.pid;
       }
       this.trace.raf.scheduleFullRedraw();
     }
   }

   onMouseOut() {
     this.hover = undefined;
     if (this.hoverMonitor.ifStateChanged()) {
       if (this.mode === 'sched') {
         this.trace.timeline.hoveredUtid = undefined;
         this.trace.timeline.hoveredPid = undefined;
       }
       this.trace.raf.scheduleFullRedraw();
     }
   }
 }
	// Copyright (C) 2025 The Android Open Source Project
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	import {BigintMath as BIMath} from '../../base/bigint_math';
	import {Monitor} from '../../base/monitor';
	import {searchEq, searchRange} from '../../base/binary_search';
	import {assertExists, assertTrue} from '../../base/logging';
	import {duration, time, Time} from '../../base/time';
	import m from 'mithril';
	import {colorForThread, colorForTid} from '../../components/colorizer';
	import {TrackData} from '../../components/tracks/track_data';
	import {TimelineFetcher} from '../../components/tracks/track_helper';
	import {checkerboardExcept} from '../../components/checkerboard';
	import {TrackRenderer} from '../../public/track';
	import {LONG, NUM, QueryResult} from '../../trace_processor/query_result';
	import {uuidv4Sql} from '../../base/uuid';
	import {
	TrackContext,
	TrackMouseEvent,
	TrackRenderContext,
	} from '../../public/track';
	import {Point2D} from '../../base/geom';
	import {TimeScale} from '../../base/time_scale';
	import {Trace} from '../../public/trace';
	import {ThreadMap} from '../dev.perfetto.Thread/threads';
	import {AsyncDisposableStack} from '../../base/disposable_stack';
	import {
	createPerfettoTable,
	createVirtualTable,
	} from '../../trace_processor/sql_utils';
	import {Dataset} from '../../trace_processor/dataset';
	import {TrackNode} from '../../public/workspace';

	export const SLICE_TRACK_SUMMARY_KIND = 'SliceTrackSummary';

	const MARGIN_TOP = 5;
	const RECT_HEIGHT = 30;
	const TRACK_HEIGHT = MARGIN_TOP * 2 + RECT_HEIGHT;

	interface Data extends TrackData {
	maxLanes: number;

	// Slices are stored in a columnar fashion. All fields have the same length.
	counts: Uint32Array;
	starts: BigInt64Array;
	ends: BigInt64Array;
	utids: Int32Array;
	lanes: Uint32Array;
	}

	export interface Config {
	pidForColor: bigint \| number;
	upid: number \| null;
	utid: number \| null;
	}

	type Mode = 'sched' \| 'slices';

	interface GroupSummaryHover {
	utid: number;
	lane: number;
	count: number;
	pid?: bigint;
	}

	function computeHover(
	pos: Point2D \| undefined,
	timescale: TimeScale,
	data: Data,
	threads: ThreadMap,
	): GroupSummaryHover \| undefined {
	if (pos === undefined) return undefined;

	const {x, y} = pos;
	if (y < MARGIN_TOP \|\| y > MARGIN_TOP + RECT_HEIGHT) return undefined;

	const laneHeight = Math.floor(RECT_HEIGHT / data.maxLanes);
	const lane = Math.floor((y - MARGIN_TOP) / (laneHeight + 1));
	const t = timescale.pxToHpTime(x).toTime('floor');

	const [i, j] = searchRange(data.starts, t, searchEq(data.lanes, lane));
	if (i === j \|\| i >= data.starts.length \|\| t > data.ends[i]) return undefined;

	const utid = data.utids[i];
	const count = data.counts[i];
	const pid = threads.get(utid)?.pid;
	return {utid, lane, count, pid};
	}

	export class GroupSummaryTrack implements TrackRenderer {
	private hover?: GroupSummaryHover;
	private fetcher = new TimelineFetcher(this.onBoundsChange.bind(this));
	private trackUuid = uuidv4Sql();
	private mode: Mode = 'slices';
	private maxLanes: number = 1;
	private sliceTracks: Array<{uri: string; dataset: Dataset}> = [];

	// Monitor for local hover state (triggers DOM redraw for tooltip).
	private readonly hoverMonitor = new Monitor([
	() => this.hover?.utid,
	() => this.hover?.lane,
	() => this.hover?.count,
	]);

	constructor(
	private readonly trace: Trace,
	private readonly config: Config,
	private readonly cpuCount: number,
	private readonly threads: ThreadMap,
	hasSched: boolean,
	) {
	this.mode = hasSched ? 'sched' : 'slices';
	}

	async onCreate(ctx: TrackContext): Promise<void> {
	if (this.mode === 'sched') {
	await this.createSchedMipmap();
	} else {
	await this.createSlicesMipmap(ctx.trackNode);
	}
	}

	private async createSchedMipmap(): Promise<void> {
	const getQuery = () => {
	if (this.config.upid !== null) {
	return `
	select
	s.id,
	s.ts,
	s.dur,
	c.cpu,
	s.utid
	from thread t
	cross join sched s using (utid)
	cross join cpu c using (ucpu)
	where
	t.is_idle = 0 and
	t.upid = ${this.config.upid}
	order by ts
	`;
	}
	assertExists(this.config.utid);
	return `
	select
	s.id,
	s.ts,
	s.dur,
	c.cpu,
	s.utid
	from sched s
	cross join cpu c using (ucpu)
	where
	s.utid = ${this.config.utid}
	`;
	};

	const trash = new AsyncDisposableStack();
	trash.use(
	await createPerfettoTable({
	engine: this.trace.engine,
	name: `tmp_${this.trackUuid}`,
	as: getQuery(),
	}),
	);
	await createVirtualTable({
	engine: this.trace.engine,
	name: `process_summary_${this.trackUuid}`,
	using: `__intrinsic_slice_mipmap((
	select
	s.id,
	s.ts,
	iif(
	s.dur = -1,
	ifnull(
	(
	select n.ts
	from tmp_${this.trackUuid} n
	where n.ts > s.ts and n.cpu = s.cpu
	order by ts
	limit 1
	),
	trace_end()
	) - s.ts,
	s.dur
	) as dur,
	s.cpu as depth
	from tmp_${this.trackUuid} s
	))`,
	});
	await trash.asyncDispose();

	this.maxLanes = this.cpuCount;
	}

	private fetchDatasetsFromSliceTracks(node: TrackNode) {
	assertTrue(
	this.mode === 'slices',
	'Can only collect slice tracks in slice mode',
	);
	const stack: TrackNode[] = [node];
	while (stack.length > 0 && this.sliceTracks.length < 8) {
	const node = stack.pop()!;

	// Try to get track and dataset
	const track =
	node.uri !== undefined
	? this.trace.tracks.getTrack(node.uri)
	: undefined;
	const dataset = track?.renderer.getDataset?.();

	// Check if it's a valid slice track WITH depth column
	const sliceSchema = {ts: LONG, dur: LONG, depth: NUM};
	const isValidSliceTrack = dataset?.implements(sliceSchema) ?? false;

	if (isValidSliceTrack && dataset !== undefined) {
	// Add track - we'll filter to depth = 0 in SQL
	this.sliceTracks.push({
	uri: node.uri!,
	dataset: dataset,
	});
	} else {
	// Not valid - traverse children
	for (let i = node.children.length - 1; i >= 0; i--) {
	stack.push(node.children[i]);
	}
	}
	}
	}

	private async createSlicesMipmap(node: TrackNode): Promise<void> {
	// Fetch datasets from child tracks
	this.fetchDatasetsFromSliceTracks(node);

	if (this.sliceTracks.length === 0) {
	// No valid slice tracks found - create empty table
	await createVirtualTable({
	engine: this.trace.engine,
	name: `process_summary_${this.trackUuid}`,
	using: `__intrinsic_slice_mipmap((
	select
	cast(0 as int) as id,
	cast(0 as bigint) as ts,
	cast(0 as bigint) as dur,
	cast(0 as int) as depth
	where 0
	))`,
	});
	this.maxLanes = 1;
	return;
	}

	// Create union of all slice tracks with track index as depth
	const unions = this.sliceTracks
	.map(({dataset}, idx) => {
	return `
	select
	id,
	ts,
	iif(dur = -1, trace_end() - ts, dur) as dur,
	${idx} as depth
	from (${dataset.query()})
	where depth = 0
	`;
	})
	.join(' union all ');

	await createVirtualTable({
	engine: this.trace.engine,
	name: `process_summary_${this.trackUuid}`,
	using: `__intrinsic_slice_mipmap((
	${unions}
	))`,
	});
	this.maxLanes = 8;
	}

	async onUpdate({
	visibleWindow,
	resolution,
	}: TrackRenderContext): Promise<void> {
	await this.fetcher.requestData(visibleWindow.toTimeSpan(), resolution);
	}

	async onDestroy(): Promise<void> {
	this.fetcher[Symbol.dispose]();
	await this.trace.engine.tryQuery(`
	drop table process_summary_${this.trackUuid}
	`);
	}

	async onBoundsChange(
	start: time,
	end: time,
	resolution: duration,
	): Promise<Data> {
	// Resolution must always be a power of 2 for this logic to work
	assertTrue(BIMath.popcount(resolution) === 1, `${resolution} not pow of 2`);

	const queryRes = await this.queryData(start, end, resolution);
	const numRows = queryRes.numRows();
	const slices: Data = {
	start,
	end,
	resolution,
	length: numRows,
	maxLanes: this.maxLanes,
	counts: new Uint32Array(numRows),
	starts: new BigInt64Array(numRows),
	ends: new BigInt64Array(numRows),
	lanes: new Uint32Array(numRows),
	utids: new Int32Array(numRows),
	};

	const it = queryRes.iter({
	count: NUM,
	ts: LONG,
	dur: LONG,
	lane: NUM,
	utid: NUM,
	});

	for (let row = 0; it.valid(); it.next(), row++) {
	const start = Time.fromRaw(it.ts);
	const dur = it.dur;
	const end = Time.add(start, dur);

	slices.counts[row] = it.count;
	slices.starts[row] = start;
	slices.ends[row] = end;
	slices.lanes[row] = it.lane;
	slices.utids[row] = it.utid;
	slices.end = Time.max(end, slices.end);
	}
	return slices;
	}

	private async queryData(
	start: time,
	end: time,
	bucketSize: duration,
	): Promise<QueryResult> {
	if (this.mode === 'sched') {
	return this.trace.engine.query(`
	select
	(z.ts / ${bucketSize}) * ${bucketSize} as ts,
	iif(s.dur = -1, s.dur, max(z.dur, ${bucketSize})) as dur,
	z.count,
	z.depth as lane,
	s.utid
	from process_summary_${this.trackUuid}(
	${start}, ${end}, ${bucketSize}
	) z
	cross join sched s using (id)
	`);
	} else {
	return this.trace.engine.query(`
	select
	(z.ts / ${bucketSize}) * ${bucketSize} as ts,
	max(z.dur, ${bucketSize}) as dur,
	z.count,
	z.depth as lane,
	-1 as utid
	from process_summary_${this.trackUuid}(
	${start}, ${end}, ${bucketSize}
	) z
	`);
	}
	}

	getHeight(): number {
	return TRACK_HEIGHT;
	}

	renderTooltip(): m.Children {
	if (this.hover === undefined) {
	return undefined;
	}

	if (this.mode === 'sched') {
	// Show thread/process info for scheduling mode
	const hoveredThread = this.threads.get(this.hover.utid);
	if (!hoveredThread) {
	return undefined;
	}

	const tidText = `T: ${hoveredThread.threadName} [${hoveredThread.tid}]`;

	const count = this.hover.count;
	const countDiv = count > 1 && m('div', `and ${count - 1} other events`);
	if (hoveredThread.pid !== undefined) {
	const pidText = `P: ${hoveredThread.procName} [${hoveredThread.pid}]`;
	return m('.tooltip', [m('div', pidText), m('div', tidText), countDiv]);
	} else {
	return m('.tooltip', tidText, countDiv);
	}
	} else {
	// Show track name/info for slice mode
	const laneIndex = this.hover.lane;
	if (laneIndex < 0 \|\| laneIndex >= this.sliceTracks.length) {
	return undefined;
	}

	const trackUri = this.sliceTracks[laneIndex].uri;
	const track = this.trace.tracks.getTrack(trackUri);
	const trackTitle = (track as {title?: string})?.title ?? trackUri;

	const count = this.hover.count;
	const countDiv = count > 1 && m('div', `${count} slices`);

	return m('.tooltip', [m('div', `Track: ${trackTitle}`), countDiv]);
	}
	}

	render({ctx, size, timescale, visibleWindow}: TrackRenderContext): void {
	const data = this.fetcher.data;

	if (data === undefined) return; // Can't possibly draw anything.

	// If the cached trace slices don't fully cover the visible time range,
	// show a gray rectangle with a "Loading..." label.
	checkerboardExcept(
	ctx,
	this.getHeight(),
	0,
	size.width,
	timescale.timeToPx(data.start),
	timescale.timeToPx(data.end),
	);

	assertTrue(data.starts.length === data.ends.length);
	assertTrue(data.starts.length === data.utids.length);

	const laneHeight = Math.floor(RECT_HEIGHT / data.maxLanes);

	for (let i = 0; i < data.ends.length; i++) {
	const tStart = Time.fromRaw(data.starts[i]);
	const tEnd = Time.fromRaw(data.ends[i]);

	// Cull slices that lie completely outside the visible window
	if (!visibleWindow.overlaps(tStart, tEnd)) continue;

	const utid = data.utids[i];
	const lane = data.lanes[i];

	const rectStart = Math.floor(timescale.timeToPx(tStart));
	const rectEnd = Math.floor(timescale.timeToPx(tEnd));
	const rectWidth = Math.max(1, rectEnd - rectStart);

	let colorScheme;

	if (this.mode === 'sched') {
	// Scheduling mode: color by thread (utid)
	const threadInfo = this.threads.get(utid);
	// eslint-disable-next-line @typescript-eslint/strict-boolean-expressions
	const pid = (threadInfo ? threadInfo.pid : -1) \|\| -1;

	const isHovering = this.trace.timeline.hoveredUtid !== undefined;
	const isThreadHovered = this.trace.timeline.hoveredUtid === utid;
	const isProcessHovered = this.trace.timeline.hoveredPid === pid;
	colorScheme = colorForThread(threadInfo);

	if (isHovering && !isThreadHovered) {
	if (!isProcessHovered) {
	ctx.fillStyle = colorScheme.disabled.cssString;
	} else {
	ctx.fillStyle = colorScheme.variant.cssString;
	}
	} else {
	ctx.fillStyle = colorScheme.base.cssString;
	}
	} else {
	// Slice mode: consistent color based on pidForColor
	colorScheme = colorForTid(this.config.pidForColor);
	ctx.fillStyle = colorScheme.base.cssString;
	}

	const y = MARGIN_TOP + laneHeight * lane + lane;
	ctx.fillRect(rectStart, y, rectWidth, laneHeight);
	}
	}

	onMouseMove({x, y, timescale}: TrackMouseEvent) {
	const data = this.fetcher.data;
	if (data === undefined) return;
	this.hover = computeHover({x, y}, timescale, data, this.threads);
	if (this.hoverMonitor.ifStateChanged()) {
	if (this.mode === 'sched') {
	this.trace.timeline.hoveredUtid = this.hover?.utid;
	this.trace.timeline.hoveredPid = this.hover?.pid;
	}
	this.trace.raf.scheduleFullRedraw();
	}
	}

	onMouseOut() {
	this.hover = undefined;
	if (this.hoverMonitor.ifStateChanged()) {
	if (this.mode === 'sched') {
	this.trace.timeline.hoveredUtid = undefined;
	this.trace.timeline.hoveredPid = undefined;
	}
	this.trace.raf.scheduleFullRedraw();
	}
	}
	}