github.com/megatontech/mynoteforgo@v0.0.0-20200507084910-5d0c6ea6e890/源码/cmd/trace/trace.go

github.com/megatontech/mynoteforgo@v0.0.0-20200507084910-5d0c6ea6e890/源码/cmd/trace/trace.go (about)

     1  // Copyright 2014 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package main
     6  
     7  import (
     8  	"encoding/json"
     9  	"fmt"
    10  	"internal/trace"
    11  	"io"
    12  	"log"
    13  	"math"
    14  	"net/http"
    15  	"path/filepath"
    16  	"runtime"
    17  	"runtime/debug"
    18  	"sort"
    19  	"strconv"
    20  	"strings"
    21  	"time"
    22  )
    23  
    24  func init() {
    25  	http.HandleFunc("/trace", httpTrace)
    26  	http.HandleFunc("/jsontrace", httpJsonTrace)
    27  	http.HandleFunc("/trace_viewer_html", httpTraceViewerHTML)
    28  }
    29  
    30  // httpTrace serves either whole trace (goid==0) or trace for goid goroutine.
    31  func httpTrace(w http.ResponseWriter, r *http.Request) {
    32  	_, err := parseTrace()
    33  	if err != nil {
    34  		http.Error(w, err.Error(), http.StatusInternalServerError)
    35  		return
    36  	}
    37  	if err := r.ParseForm(); err != nil {
    38  		http.Error(w, err.Error(), http.StatusInternalServerError)
    39  		return
    40  	}
    41  	html := strings.ReplaceAll(templTrace, "{{PARAMS}}", r.Form.Encode())
    42  	w.Write([]byte(html))
    43  
    44  }
    45  
    46  // See https://github.com/catapult-project/catapult/blob/master/tracing/docs/embedding-trace-viewer.md
    47  // This is almost verbatim copy of:
    48  // https://github.com/catapult-project/catapult/blob/master/tracing/bin/index.html
    49  // on revision 5f9e4c3eaa555bdef18218a89f38c768303b7b6e.
    50  var templTrace = `
    51  <html>
    52  <head>
    53  <link href="/trace_viewer_html" rel="import">
    54  <style type="text/css">
    55    html, body {
    56      box-sizing: border-box;
    57      overflow: hidden;
    58      margin: 0px;
    59      padding: 0;
    60      width: 100%;
    61      height: 100%;
    62    }
    63    #trace-viewer {
    64      width: 100%;
    65      height: 100%;
    66    }
    67    #trace-viewer:focus {
    68      outline: none;
    69    }
    70  </style>
    71  <script>
    72  'use strict';
    73  (function() {
    74    var viewer;
    75    var url;
    76    var model;
    77  
    78    function load() {
    79      var req = new XMLHttpRequest();
    80      var is_binary = /[.]gz$/.test(url) || /[.]zip$/.test(url);
    81      req.overrideMimeType('text/plain; charset=x-user-defined');
    82      req.open('GET', url, true);
    83      if (is_binary)
    84        req.responseType = 'arraybuffer';
    85  
    86      req.onreadystatechange = function(event) {
    87        if (req.readyState !== 4)
    88          return;
    89  
    90        window.setTimeout(function() {
    91          if (req.status === 200)
    92            onResult(is_binary ? req.response : req.responseText);
    93          else
    94            onResultFail(req.status);
    95        }, 0);
    96      };
    97      req.send(null);
    98    }
    99  
   100    function onResultFail(err) {
   101      var overlay = new tr.ui.b.Overlay();
   102      overlay.textContent = err + ': ' + url + ' could not be loaded';
   103      overlay.title = 'Failed to fetch data';
   104      overlay.visible = true;
   105    }
   106  
   107    function onResult(result) {
   108      model = new tr.Model();
   109      var opts = new tr.importer.ImportOptions();
   110      opts.shiftWorldToZero = false;
   111      var i = new tr.importer.Import(model, opts);
   112      var p = i.importTracesWithProgressDialog([result]);
   113      p.then(onModelLoaded, onImportFail);
   114    }
   115  
   116    function onModelLoaded() {
   117      viewer.model = model;
   118      viewer.viewTitle = "trace";
   119  
   120      if (!model || model.bounds.isEmpty)
   121        return;
   122      var sel = window.location.hash.substr(1);
   123      if (sel === '')
   124        return;
   125      var parts = sel.split(':');
   126      var range = new (tr.b.Range || tr.b.math.Range)();
   127      range.addValue(parseFloat(parts[0]));
   128      range.addValue(parseFloat(parts[1]));
   129      viewer.trackView.viewport.interestRange.set(range);
   130    }
   131  
   132    function onImportFail(err) {
   133      var overlay = new tr.ui.b.Overlay();
   134      overlay.textContent = tr.b.normalizeException(err).message;
   135      overlay.title = 'Import error';
   136      overlay.visible = true;
   137    }
   138  
   139    document.addEventListener('DOMContentLoaded', function() {
   140      var container = document.createElement('track-view-container');
   141      container.id = 'track_view_container';
   142  
   143      viewer = document.createElement('tr-ui-timeline-view');
   144      viewer.track_view_container = container;
   145      viewer.appendChild(container);
   146  
   147      viewer.id = 'trace-viewer';
   148      viewer.globalMode = true;
   149      document.body.appendChild(viewer);
   150  
   151      url = '/jsontrace?{{PARAMS}}';
   152      load();
   153    });
   154  }());
   155  </script>
   156  </head>
   157  <body>
   158  </body>
   159  </html>
   160  `
   161  
   162  // httpTraceViewerHTML serves static part of trace-viewer.
   163  // This URL is queried from templTrace HTML.
   164  func httpTraceViewerHTML(w http.ResponseWriter, r *http.Request) {
   165  	http.ServeFile(w, r, filepath.Join(runtime.GOROOT(), "misc", "trace", "trace_viewer_full.html"))
   166  }
   167  
   168  // httpJsonTrace serves json trace, requested from within templTrace HTML.
   169  func httpJsonTrace(w http.ResponseWriter, r *http.Request) {
   170  	defer debug.FreeOSMemory()
   171  	defer reportMemoryUsage("after httpJsonTrace")
   172  	// This is an AJAX handler, so instead of http.Error we use log.Printf to log errors.
   173  	res, err := parseTrace()
   174  	if err != nil {
   175  		log.Printf("failed to parse trace: %v", err)
   176  		return
   177  	}
   178  
   179  	params := &traceParams{
   180  		parsed:  res,
   181  		endTime: math.MaxInt64,
   182  	}
   183  
   184  	if goids := r.FormValue("goid"); goids != "" {
   185  		// If goid argument is present, we are rendering a trace for this particular goroutine.
   186  		goid, err := strconv.ParseUint(goids, 10, 64)
   187  		if err != nil {
   188  			log.Printf("failed to parse goid parameter %q: %v", goids, err)
   189  			return
   190  		}
   191  		analyzeGoroutines(res.Events)
   192  		g, ok := gs[goid]
   193  		if !ok {
   194  			log.Printf("failed to find goroutine %d", goid)
   195  			return
   196  		}
   197  		params.mode = modeGoroutineOriented
   198  		params.startTime = g.StartTime
   199  		if g.EndTime != 0 {
   200  			params.endTime = g.EndTime
   201  		} else { // The goroutine didn't end.
   202  			params.endTime = lastTimestamp()
   203  		}
   204  		params.maing = goid
   205  		params.gs = trace.RelatedGoroutines(res.Events, goid)
   206  	} else if taskids := r.FormValue("taskid"); taskids != "" {
   207  		taskid, err := strconv.ParseUint(taskids, 10, 64)
   208  		if err != nil {
   209  			log.Printf("failed to parse taskid parameter %q: %v", taskids, err)
   210  			return
   211  		}
   212  		annotRes, _ := analyzeAnnotations()
   213  		task, ok := annotRes.tasks[taskid]
   214  		if !ok || len(task.events) == 0 {
   215  			log.Printf("failed to find task with id %d", taskid)
   216  			return
   217  		}
   218  		goid := task.events[0].G
   219  		params.mode = modeGoroutineOriented | modeTaskOriented
   220  		params.startTime = task.firstTimestamp() - 1
   221  		params.endTime = task.lastTimestamp() + 1
   222  		params.maing = goid
   223  		params.tasks = task.descendants()
   224  		gs := map[uint64]bool{}
   225  		for _, t := range params.tasks {
   226  			// find only directly involved goroutines
   227  			for k, v := range t.RelatedGoroutines(res.Events, 0) {
   228  				gs[k] = v
   229  			}
   230  		}
   231  		params.gs = gs
   232  	} else if taskids := r.FormValue("focustask"); taskids != "" {
   233  		taskid, err := strconv.ParseUint(taskids, 10, 64)
   234  		if err != nil {
   235  			log.Printf("failed to parse focustask parameter %q: %v", taskids, err)
   236  			return
   237  		}
   238  		annotRes, _ := analyzeAnnotations()
   239  		task, ok := annotRes.tasks[taskid]
   240  		if !ok || len(task.events) == 0 {
   241  			log.Printf("failed to find task with id %d", taskid)
   242  			return
   243  		}
   244  		params.mode = modeTaskOriented
   245  		params.startTime = task.firstTimestamp() - 1
   246  		params.endTime = task.lastTimestamp() + 1
   247  		params.tasks = task.descendants()
   248  	}
   249  
   250  	start := int64(0)
   251  	end := int64(math.MaxInt64)
   252  	if startStr, endStr := r.FormValue("start"), r.FormValue("end"); startStr != "" && endStr != "" {
   253  		// If start/end arguments are present, we are rendering a range of the trace.
   254  		start, err = strconv.ParseInt(startStr, 10, 64)
   255  		if err != nil {
   256  			log.Printf("failed to parse start parameter %q: %v", startStr, err)
   257  			return
   258  		}
   259  		end, err = strconv.ParseInt(endStr, 10, 64)
   260  		if err != nil {
   261  			log.Printf("failed to parse end parameter %q: %v", endStr, err)
   262  			return
   263  		}
   264  	}
   265  
   266  	c := viewerDataTraceConsumer(w, start, end)
   267  	if err := generateTrace(params, c); err != nil {
   268  		log.Printf("failed to generate trace: %v", err)
   269  		return
   270  	}
   271  }
   272  
   273  type Range struct {
   274  	Name      string
   275  	Start     int
   276  	End       int
   277  	StartTime int64
   278  	EndTime   int64
   279  }
   280  
   281  func (r Range) URL() string {
   282  	return fmt.Sprintf("/trace?start=%d&end=%d", r.Start, r.End)
   283  }
   284  
   285  // splitTrace splits the trace into a number of ranges,
   286  // each resulting in approx 100MB of json output
   287  // (trace viewer can hardly handle more).
   288  func splitTrace(res trace.ParseResult) []Range {
   289  	params := &traceParams{
   290  		parsed:  res,
   291  		endTime: math.MaxInt64,
   292  	}
   293  	s, c := splittingTraceConsumer(100 << 20) // 100M
   294  	if err := generateTrace(params, c); err != nil {
   295  		dief("%v\n", err)
   296  	}
   297  	return s.Ranges
   298  }
   299  
   300  type splitter struct {
   301  	Ranges []Range
   302  }
   303  
   304  func splittingTraceConsumer(max int) (*splitter, traceConsumer) {
   305  	type eventSz struct {
   306  		Time float64
   307  		Sz   int
   308  	}
   309  
   310  	var (
   311  		data = ViewerData{Frames: make(map[string]ViewerFrame)}
   312  
   313  		sizes []eventSz
   314  		cw    countingWriter
   315  	)
   316  
   317  	s := new(splitter)
   318  
   319  	return s, traceConsumer{
   320  		consumeTimeUnit: func(unit string) {
   321  			data.TimeUnit = unit
   322  		},
   323  		consumeViewerEvent: func(v *ViewerEvent, required bool) {
   324  			if required {
   325  				// Store required events inside data
   326  				// so flush can include them in the required
   327  				// part of the trace.
   328  				data.Events = append(data.Events, v)
   329  				return
   330  			}
   331  			enc := json.NewEncoder(&cw)
   332  			enc.Encode(v)
   333  			sizes = append(sizes, eventSz{v.Time, cw.size + 1}) // +1 for ",".
   334  			cw.size = 0
   335  		},
   336  		consumeViewerFrame: func(k string, v ViewerFrame) {
   337  			data.Frames[k] = v
   338  		},
   339  		flush: func() {
   340  			// Calculate size of the mandatory part of the trace.
   341  			// This includes stack traces and thread names.
   342  			cw.size = 0
   343  			enc := json.NewEncoder(&cw)
   344  			enc.Encode(data)
   345  			minSize := cw.size
   346  
   347  			// Then calculate size of each individual event
   348  			// and group them into ranges.
   349  			sum := minSize
   350  			start := 0
   351  			for i, ev := range sizes {
   352  				if sum+ev.Sz > max {
   353  					startTime := time.Duration(sizes[start].Time * 1000)
   354  					endTime := time.Duration(ev.Time * 1000)
   355  					ranges = append(ranges, Range{
   356  						Name:      fmt.Sprintf("%v-%v", startTime, endTime),
   357  						Start:     start,
   358  						End:       i + 1,
   359  						StartTime: int64(startTime),
   360  						EndTime:   int64(endTime),
   361  					})
   362  					start = i + 1
   363  					sum = minSize
   364  				} else {
   365  					sum += ev.Sz + 1
   366  				}
   367  			}
   368  			if len(ranges) <= 1 {
   369  				s.Ranges = nil
   370  				return
   371  			}
   372  
   373  			if end := len(sizes) - 1; start < end {
   374  				ranges = append(ranges, Range{
   375  					Name:      fmt.Sprintf("%v-%v", time.Duration(sizes[start].Time*1000), time.Duration(sizes[end].Time*1000)),
   376  					Start:     start,
   377  					End:       end,
   378  					StartTime: int64(sizes[start].Time * 1000),
   379  					EndTime:   int64(sizes[end].Time * 1000),
   380  				})
   381  			}
   382  			s.Ranges = ranges
   383  		},
   384  	}
   385  }
   386  
   387  type countingWriter struct {
   388  	size int
   389  }
   390  
   391  func (cw *countingWriter) Write(data []byte) (int, error) {
   392  	cw.size += len(data)
   393  	return len(data), nil
   394  }
   395  
   396  type traceParams struct {
   397  	parsed    trace.ParseResult
   398  	mode      traceviewMode
   399  	startTime int64
   400  	endTime   int64
   401  	maing     uint64          // for goroutine-oriented view, place this goroutine on the top row
   402  	gs        map[uint64]bool // Goroutines to be displayed for goroutine-oriented or task-oriented view
   403  	tasks     []*taskDesc     // Tasks to be displayed. tasks[0] is the top-most task
   404  }
   405  
   406  type traceviewMode uint
   407  
   408  const (
   409  	modeGoroutineOriented traceviewMode = 1 << iota
   410  	modeTaskOriented
   411  )
   412  
   413  type traceContext struct {
   414  	*traceParams
   415  	consumer  traceConsumer
   416  	frameTree frameNode
   417  	frameSeq  int
   418  	arrowSeq  uint64
   419  	gcount    uint64
   420  
   421  	heapStats, prevHeapStats     heapStats
   422  	threadStats, prevThreadStats threadStats
   423  	gstates, prevGstates         [gStateCount]int64
   424  
   425  	regionID int // last emitted region id. incremented in each emitRegion call.
   426  }
   427  
   428  type heapStats struct {
   429  	heapAlloc uint64
   430  	nextGC    uint64
   431  }
   432  
   433  type threadStats struct {
   434  	insyscallRuntime int64 // system goroutine in syscall
   435  	insyscall        int64 // user goroutine in syscall
   436  	prunning         int64 // thread running P
   437  }
   438  
   439  type frameNode struct {
   440  	id       int
   441  	children map[uint64]frameNode
   442  }
   443  
   444  type gState int
   445  
   446  const (
   447  	gDead gState = iota
   448  	gRunnable
   449  	gRunning
   450  	gWaiting
   451  	gWaitingGC
   452  
   453  	gStateCount
   454  )
   455  
   456  type gInfo struct {
   457  	state      gState // current state
   458  	name       string // name chosen for this goroutine at first EvGoStart
   459  	isSystemG  bool
   460  	start      *trace.Event // most recent EvGoStart
   461  	markAssist *trace.Event // if non-nil, the mark assist currently running.
   462  }
   463  
   464  type ViewerData struct {
   465  	Events   []*ViewerEvent         `json:"traceEvents"`
   466  	Frames   map[string]ViewerFrame `json:"stackFrames"`
   467  	TimeUnit string                 `json:"displayTimeUnit"`
   468  
   469  	// This is where mandatory part of the trace starts (e.g. thread names)
   470  	footer int
   471  }
   472  
   473  type ViewerEvent struct {
   474  	Name     string      `json:"name,omitempty"`
   475  	Phase    string      `json:"ph"`
   476  	Scope    string      `json:"s,omitempty"`
   477  	Time     float64     `json:"ts"`
   478  	Dur      float64     `json:"dur,omitempty"`
   479  	Pid      uint64      `json:"pid"`
   480  	Tid      uint64      `json:"tid"`
   481  	ID       uint64      `json:"id,omitempty"`
   482  	Stack    int         `json:"sf,omitempty"`
   483  	EndStack int         `json:"esf,omitempty"`
   484  	Arg      interface{} `json:"args,omitempty"`
   485  	Cname    string      `json:"cname,omitempty"`
   486  	Category string      `json:"cat,omitempty"`
   487  }
   488  
   489  type ViewerFrame struct {
   490  	Name   string `json:"name"`
   491  	Parent int    `json:"parent,omitempty"`
   492  }
   493  
   494  type NameArg struct {
   495  	Name string `json:"name"`
   496  }
   497  
   498  type TaskArg struct {
   499  	ID     uint64 `json:"id"`
   500  	StartG uint64 `json:"start_g,omitempty"`
   501  	EndG   uint64 `json:"end_g,omitempty"`
   502  }
   503  
   504  type RegionArg struct {
   505  	TaskID uint64 `json:"taskid,omitempty"`
   506  }
   507  
   508  type SortIndexArg struct {
   509  	Index int `json:"sort_index"`
   510  }
   511  
   512  type traceConsumer struct {
   513  	consumeTimeUnit    func(unit string)
   514  	consumeViewerEvent func(v *ViewerEvent, required bool)
   515  	consumeViewerFrame func(key string, f ViewerFrame)
   516  	flush              func()
   517  }
   518  
   519  const (
   520  	procsSection = 0 // where Goroutines or per-P timelines are presented.
   521  	statsSection = 1 // where counters are presented.
   522  	tasksSection = 2 // where Task hierarchy & timeline is presented.
   523  )
   524  
   525  // generateTrace generates json trace for trace-viewer:
   526  // https://github.com/google/trace-viewer
   527  // Trace format is described at:
   528  // https://docs.google.com/document/d/1CvAClvFfyA5R-PhYUmn5OOQtYMH4h6I0nSsKchNAySU/view
   529  // If mode==goroutineMode, generate trace for goroutine goid, otherwise whole trace.
   530  // startTime, endTime determine part of the trace that we are interested in.
   531  // gset restricts goroutines that are included in the resulting trace.
   532  func generateTrace(params *traceParams, consumer traceConsumer) error {
   533  	defer consumer.flush()
   534  
   535  	ctx := &traceContext{traceParams: params}
   536  	ctx.frameTree.children = make(map[uint64]frameNode)
   537  	ctx.consumer = consumer
   538  
   539  	ctx.consumer.consumeTimeUnit("ns")
   540  	maxProc := 0
   541  	ginfos := make(map[uint64]*gInfo)
   542  	stacks := params.parsed.Stacks
   543  
   544  	getGInfo := func(g uint64) *gInfo {
   545  		info, ok := ginfos[g]
   546  		if !ok {
   547  			info = &gInfo{}
   548  			ginfos[g] = info
   549  		}
   550  		return info
   551  	}
   552  
   553  	// Since we make many calls to setGState, we record a sticky
   554  	// error in setGStateErr and check it after every event.
   555  	var setGStateErr error
   556  	setGState := func(ev *trace.Event, g uint64, oldState, newState gState) {
   557  		info := getGInfo(g)
   558  		if oldState == gWaiting && info.state == gWaitingGC {
   559  			// For checking, gWaiting counts as any gWaiting*.
   560  			oldState = info.state
   561  		}
   562  		if info.state != oldState && setGStateErr == nil {
   563  			setGStateErr = fmt.Errorf("expected G %d to be in state %d, but got state %d", g, oldState, newState)
   564  		}
   565  		ctx.gstates[info.state]--
   566  		ctx.gstates[newState]++
   567  		info.state = newState
   568  	}
   569  
   570  	for _, ev := range ctx.parsed.Events {
   571  		// Handle state transitions before we filter out events.
   572  		switch ev.Type {
   573  		case trace.EvGoStart, trace.EvGoStartLabel:
   574  			setGState(ev, ev.G, gRunnable, gRunning)
   575  			info := getGInfo(ev.G)
   576  			info.start = ev
   577  		case trace.EvProcStart:
   578  			ctx.threadStats.prunning++
   579  		case trace.EvProcStop:
   580  			ctx.threadStats.prunning--
   581  		case trace.EvGoCreate:
   582  			newG := ev.Args[0]
   583  			info := getGInfo(newG)
   584  			if info.name != "" {
   585  				return fmt.Errorf("duplicate go create event for go id=%d detected at offset %d", newG, ev.Off)
   586  			}
   587  
   588  			stk, ok := stacks[ev.Args[1]]
   589  			if !ok || len(stk) == 0 {
   590  				return fmt.Errorf("invalid go create event: missing stack information for go id=%d at offset %d", newG, ev.Off)
   591  			}
   592  
   593  			fname := stk[0].Fn
   594  			info.name = fmt.Sprintf("G%v %s", newG, fname)
   595  			info.isSystemG = isSystemGoroutine(fname)
   596  
   597  			ctx.gcount++
   598  			setGState(ev, newG, gDead, gRunnable)
   599  		case trace.EvGoEnd:
   600  			ctx.gcount--
   601  			setGState(ev, ev.G, gRunning, gDead)
   602  		case trace.EvGoUnblock:
   603  			setGState(ev, ev.Args[0], gWaiting, gRunnable)
   604  		case trace.EvGoSysExit:
   605  			setGState(ev, ev.G, gWaiting, gRunnable)
   606  			if getGInfo(ev.G).isSystemG {
   607  				ctx.threadStats.insyscallRuntime--
   608  			} else {
   609  				ctx.threadStats.insyscall--
   610  			}
   611  		case trace.EvGoSysBlock:
   612  			setGState(ev, ev.G, gRunning, gWaiting)
   613  			if getGInfo(ev.G).isSystemG {
   614  				ctx.threadStats.insyscallRuntime++
   615  			} else {
   616  				ctx.threadStats.insyscall++
   617  			}
   618  		case trace.EvGoSched, trace.EvGoPreempt:
   619  			setGState(ev, ev.G, gRunning, gRunnable)
   620  		case trace.EvGoStop,
   621  			trace.EvGoSleep, trace.EvGoBlock, trace.EvGoBlockSend, trace.EvGoBlockRecv,
   622  			trace.EvGoBlockSelect, trace.EvGoBlockSync, trace.EvGoBlockCond, trace.EvGoBlockNet:
   623  			setGState(ev, ev.G, gRunning, gWaiting)
   624  		case trace.EvGoBlockGC:
   625  			setGState(ev, ev.G, gRunning, gWaitingGC)
   626  		case trace.EvGCMarkAssistStart:
   627  			getGInfo(ev.G).markAssist = ev
   628  		case trace.EvGCMarkAssistDone:
   629  			getGInfo(ev.G).markAssist = nil
   630  		case trace.EvGoWaiting:
   631  			setGState(ev, ev.G, gRunnable, gWaiting)
   632  		case trace.EvGoInSyscall:
   633  			// Cancel out the effect of EvGoCreate at the beginning.
   634  			setGState(ev, ev.G, gRunnable, gWaiting)
   635  			if getGInfo(ev.G).isSystemG {
   636  				ctx.threadStats.insyscallRuntime++
   637  			} else {
   638  				ctx.threadStats.insyscall++
   639  			}
   640  		case trace.EvHeapAlloc:
   641  			ctx.heapStats.heapAlloc = ev.Args[0]
   642  		case trace.EvNextGC:
   643  			ctx.heapStats.nextGC = ev.Args[0]
   644  		}
   645  		if setGStateErr != nil {
   646  			return setGStateErr
   647  		}
   648  		if ctx.gstates[gRunnable] < 0 || ctx.gstates[gRunning] < 0 || ctx.threadStats.insyscall < 0 || ctx.threadStats.insyscallRuntime < 0 {
   649  			return fmt.Errorf("invalid state after processing %v: runnable=%d running=%d insyscall=%d insyscallRuntime=%d", ev, ctx.gstates[gRunnable], ctx.gstates[gRunning], ctx.threadStats.insyscall, ctx.threadStats.insyscallRuntime)
   650  		}
   651  
   652  		// Ignore events that are from uninteresting goroutines
   653  		// or outside of the interesting timeframe.
   654  		if ctx.gs != nil && ev.P < trace.FakeP && !ctx.gs[ev.G] {
   655  			continue
   656  		}
   657  		if !withinTimeRange(ev, ctx.startTime, ctx.endTime) {
   658  			continue
   659  		}
   660  
   661  		if ev.P < trace.FakeP && ev.P > maxProc {
   662  			maxProc = ev.P
   663  		}
   664  
   665  		// Emit trace objects.
   666  		switch ev.Type {
   667  		case trace.EvProcStart:
   668  			if ctx.mode&modeGoroutineOriented != 0 {
   669  				continue
   670  			}
   671  			ctx.emitInstant(ev, "proc start", "")
   672  		case trace.EvProcStop:
   673  			if ctx.mode&modeGoroutineOriented != 0 {
   674  				continue
   675  			}
   676  			ctx.emitInstant(ev, "proc stop", "")
   677  		case trace.EvGCStart:
   678  			ctx.emitSlice(ev, "GC")
   679  		case trace.EvGCDone:
   680  		case trace.EvGCSTWStart:
   681  			if ctx.mode&modeGoroutineOriented != 0 {
   682  				continue
   683  			}
   684  			ctx.emitSlice(ev, fmt.Sprintf("STW (%s)", ev.SArgs[0]))
   685  		case trace.EvGCSTWDone:
   686  		case trace.EvGCMarkAssistStart:
   687  			// Mark assists can continue past preemptions, so truncate to the
   688  			// whichever comes first. We'll synthesize another slice if
   689  			// necessary in EvGoStart.
   690  			markFinish := ev.Link
   691  			goFinish := getGInfo(ev.G).start.Link
   692  			fakeMarkStart := *ev
   693  			text := "MARK ASSIST"
   694  			if markFinish == nil || markFinish.Ts > goFinish.Ts {
   695  				fakeMarkStart.Link = goFinish
   696  				text = "MARK ASSIST (unfinished)"
   697  			}
   698  			ctx.emitSlice(&fakeMarkStart, text)
   699  		case trace.EvGCSweepStart:
   700  			slice := ctx.makeSlice(ev, "SWEEP")
   701  			if done := ev.Link; done != nil && done.Args[0] != 0 {
   702  				slice.Arg = struct {
   703  					Swept     uint64 `json:"Swept bytes"`
   704  					Reclaimed uint64 `json:"Reclaimed bytes"`
   705  				}{done.Args[0], done.Args[1]}
   706  			}
   707  			ctx.emit(slice)
   708  		case trace.EvGoStart, trace.EvGoStartLabel:
   709  			info := getGInfo(ev.G)
   710  			if ev.Type == trace.EvGoStartLabel {
   711  				ctx.emitSlice(ev, ev.SArgs[0])
   712  			} else {
   713  				ctx.emitSlice(ev, info.name)
   714  			}
   715  			if info.markAssist != nil {
   716  				// If we're in a mark assist, synthesize a new slice, ending
   717  				// either when the mark assist ends or when we're descheduled.
   718  				markFinish := info.markAssist.Link
   719  				goFinish := ev.Link
   720  				fakeMarkStart := *ev
   721  				text := "MARK ASSIST (resumed, unfinished)"
   722  				if markFinish != nil && markFinish.Ts < goFinish.Ts {
   723  					fakeMarkStart.Link = markFinish
   724  					text = "MARK ASSIST (resumed)"
   725  				}
   726  				ctx.emitSlice(&fakeMarkStart, text)
   727  			}
   728  		case trace.EvGoCreate:
   729  			ctx.emitArrow(ev, "go")
   730  		case trace.EvGoUnblock:
   731  			ctx.emitArrow(ev, "unblock")
   732  		case trace.EvGoSysCall:
   733  			ctx.emitInstant(ev, "syscall", "")
   734  		case trace.EvGoSysExit:
   735  			ctx.emitArrow(ev, "sysexit")
   736  		case trace.EvUserLog:
   737  			ctx.emitInstant(ev, formatUserLog(ev), "user event")
   738  		case trace.EvUserTaskCreate:
   739  			ctx.emitInstant(ev, "task start", "user event")
   740  		case trace.EvUserTaskEnd:
   741  			ctx.emitInstant(ev, "task end", "user event")
   742  		}
   743  		// Emit any counter updates.
   744  		ctx.emitThreadCounters(ev)
   745  		ctx.emitHeapCounters(ev)
   746  		ctx.emitGoroutineCounters(ev)
   747  	}
   748  
   749  	ctx.emitSectionFooter(statsSection, "STATS", 0)
   750  
   751  	if ctx.mode&modeTaskOriented != 0 {
   752  		ctx.emitSectionFooter(tasksSection, "TASKS", 1)
   753  	}
   754  
   755  	if ctx.mode&modeGoroutineOriented != 0 {
   756  		ctx.emitSectionFooter(procsSection, "G", 2)
   757  	} else {
   758  		ctx.emitSectionFooter(procsSection, "PROCS", 2)
   759  	}
   760  
   761  	ctx.emitFooter(&ViewerEvent{Name: "thread_name", Phase: "M", Pid: procsSection, Tid: trace.GCP, Arg: &NameArg{"GC"}})
   762  	ctx.emitFooter(&ViewerEvent{Name: "thread_sort_index", Phase: "M", Pid: procsSection, Tid: trace.GCP, Arg: &SortIndexArg{-6}})
   763  
   764  	ctx.emitFooter(&ViewerEvent{Name: "thread_name", Phase: "M", Pid: procsSection, Tid: trace.NetpollP, Arg: &NameArg{"Network"}})
   765  	ctx.emitFooter(&ViewerEvent{Name: "thread_sort_index", Phase: "M", Pid: procsSection, Tid: trace.NetpollP, Arg: &SortIndexArg{-5}})
   766  
   767  	ctx.emitFooter(&ViewerEvent{Name: "thread_name", Phase: "M", Pid: procsSection, Tid: trace.TimerP, Arg: &NameArg{"Timers"}})
   768  	ctx.emitFooter(&ViewerEvent{Name: "thread_sort_index", Phase: "M", Pid: procsSection, Tid: trace.TimerP, Arg: &SortIndexArg{-4}})
   769  
   770  	ctx.emitFooter(&ViewerEvent{Name: "thread_name", Phase: "M", Pid: procsSection, Tid: trace.SyscallP, Arg: &NameArg{"Syscalls"}})
   771  	ctx.emitFooter(&ViewerEvent{Name: "thread_sort_index", Phase: "M", Pid: procsSection, Tid: trace.SyscallP, Arg: &SortIndexArg{-3}})
   772  
   773  	// Display rows for Ps if we are in the default trace view mode (not goroutine-oriented presentation)
   774  	if ctx.mode&modeGoroutineOriented == 0 {
   775  		for i := 0; i <= maxProc; i++ {
   776  			ctx.emitFooter(&ViewerEvent{Name: "thread_name", Phase: "M", Pid: procsSection, Tid: uint64(i), Arg: &NameArg{fmt.Sprintf("Proc %v", i)}})
   777  			ctx.emitFooter(&ViewerEvent{Name: "thread_sort_index", Phase: "M", Pid: procsSection, Tid: uint64(i), Arg: &SortIndexArg{i}})
   778  		}
   779  	}
   780  
   781  	// Display task and its regions if we are in task-oriented presentation mode.
   782  	if ctx.mode&modeTaskOriented != 0 {
   783  		// sort tasks based on the task start time.
   784  		sortedTask := make([]*taskDesc, 0, len(ctx.tasks))
   785  		for _, task := range ctx.tasks {
   786  			sortedTask = append(sortedTask, task)
   787  		}
   788  		sort.SliceStable(sortedTask, func(i, j int) bool {
   789  			ti, tj := sortedTask[i], sortedTask[j]
   790  			if ti.firstTimestamp() == tj.firstTimestamp() {
   791  				return ti.lastTimestamp() < tj.lastTimestamp()
   792  			}
   793  			return ti.firstTimestamp() < tj.firstTimestamp()
   794  		})
   795  
   796  		for i, task := range sortedTask {
   797  			ctx.emitTask(task, i)
   798  
   799  			// If we are in goroutine-oriented mode, we draw regions.
   800  			// TODO(hyangah): add this for task/P-oriented mode (i.e., focustask view) too.
   801  			if ctx.mode&modeGoroutineOriented != 0 {
   802  				for _, s := range task.regions {
   803  					ctx.emitRegion(s)
   804  				}
   805  			}
   806  		}
   807  	}
   808  
   809  	// Display goroutine rows if we are either in goroutine-oriented mode.
   810  	if ctx.mode&modeGoroutineOriented != 0 {
   811  		for k, v := range ginfos {
   812  			if !ctx.gs[k] {
   813  				continue
   814  			}
   815  			ctx.emitFooter(&ViewerEvent{Name: "thread_name", Phase: "M", Pid: procsSection, Tid: k, Arg: &NameArg{v.name}})
   816  		}
   817  		// Row for the main goroutine (maing)
   818  		ctx.emitFooter(&ViewerEvent{Name: "thread_sort_index", Phase: "M", Pid: procsSection, Tid: ctx.maing, Arg: &SortIndexArg{-2}})
   819  		// Row for GC or global state (specified with G=0)
   820  		ctx.emitFooter(&ViewerEvent{Name: "thread_sort_index", Phase: "M", Pid: procsSection, Tid: 0, Arg: &SortIndexArg{-1}})
   821  	}
   822  
   823  	return nil
   824  }
   825  
   826  func (ctx *traceContext) emit(e *ViewerEvent) {
   827  	ctx.consumer.consumeViewerEvent(e, false)
   828  }
   829  
   830  func (ctx *traceContext) emitFooter(e *ViewerEvent) {
   831  	ctx.consumer.consumeViewerEvent(e, true)
   832  }
   833  func (ctx *traceContext) emitSectionFooter(sectionID uint64, name string, priority int) {
   834  	ctx.emitFooter(&ViewerEvent{Name: "process_name", Phase: "M", Pid: sectionID, Arg: &NameArg{name}})
   835  	ctx.emitFooter(&ViewerEvent{Name: "process_sort_index", Phase: "M", Pid: sectionID, Arg: &SortIndexArg{priority}})
   836  }
   837  
   838  func (ctx *traceContext) time(ev *trace.Event) float64 {
   839  	// Trace viewer wants timestamps in microseconds.
   840  	return float64(ev.Ts) / 1000
   841  }
   842  
   843  func withinTimeRange(ev *trace.Event, s, e int64) bool {
   844  	if evEnd := ev.Link; evEnd != nil {
   845  		return ev.Ts <= e && evEnd.Ts >= s
   846  	}
   847  	return ev.Ts >= s && ev.Ts <= e
   848  }
   849  
   850  func tsWithinRange(ts, s, e int64) bool {
   851  	return s <= ts && ts <= e
   852  }
   853  
   854  func (ctx *traceContext) proc(ev *trace.Event) uint64 {
   855  	if ctx.mode&modeGoroutineOriented != 0 && ev.P < trace.FakeP {
   856  		return ev.G
   857  	} else {
   858  		return uint64(ev.P)
   859  	}
   860  }
   861  
   862  func (ctx *traceContext) emitSlice(ev *trace.Event, name string) {
   863  	ctx.emit(ctx.makeSlice(ev, name))
   864  }
   865  
   866  func (ctx *traceContext) makeSlice(ev *trace.Event, name string) *ViewerEvent {
   867  	// If ViewerEvent.Dur is not a positive value,
   868  	// trace viewer handles it as a non-terminating time interval.
   869  	// Avoid it by setting the field with a small value.
   870  	durationUsec := ctx.time(ev.Link) - ctx.time(ev)
   871  	if ev.Link.Ts-ev.Ts <= 0 {
   872  		durationUsec = 0.0001 // 0.1 nanoseconds
   873  	}
   874  	sl := &ViewerEvent{
   875  		Name:     name,
   876  		Phase:    "X",
   877  		Time:     ctx.time(ev),
   878  		Dur:      durationUsec,
   879  		Tid:      ctx.proc(ev),
   880  		Stack:    ctx.stack(ev.Stk),
   881  		EndStack: ctx.stack(ev.Link.Stk),
   882  	}
   883  
   884  	// grey out non-overlapping events if the event is not a global event (ev.G == 0)
   885  	if ctx.mode&modeTaskOriented != 0 && ev.G != 0 {
   886  		// include P information.
   887  		if t := ev.Type; t == trace.EvGoStart || t == trace.EvGoStartLabel {
   888  			type Arg struct {
   889  				P int
   890  			}
   891  			sl.Arg = &Arg{P: ev.P}
   892  		}
   893  		// grey out non-overlapping events.
   894  		overlapping := false
   895  		for _, task := range ctx.tasks {
   896  			if _, overlapped := task.overlappingDuration(ev); overlapped {
   897  				overlapping = true
   898  				break
   899  			}
   900  		}
   901  		if !overlapping {
   902  			sl.Cname = colorLightGrey
   903  		}
   904  	}
   905  	return sl
   906  }
   907  
   908  func (ctx *traceContext) emitTask(task *taskDesc, sortIndex int) {
   909  	taskRow := uint64(task.id)
   910  	taskName := task.name
   911  	durationUsec := float64(task.lastTimestamp()-task.firstTimestamp()) / 1e3
   912  
   913  	ctx.emitFooter(&ViewerEvent{Name: "thread_name", Phase: "M", Pid: tasksSection, Tid: taskRow, Arg: &NameArg{fmt.Sprintf("T%d %s", task.id, taskName)}})
   914  	ctx.emit(&ViewerEvent{Name: "thread_sort_index", Phase: "M", Pid: tasksSection, Tid: taskRow, Arg: &SortIndexArg{sortIndex}})
   915  	ts := float64(task.firstTimestamp()) / 1e3
   916  	sl := &ViewerEvent{
   917  		Name:  taskName,
   918  		Phase: "X",
   919  		Time:  ts,
   920  		Dur:   durationUsec,
   921  		Pid:   tasksSection,
   922  		Tid:   taskRow,
   923  		Cname: pickTaskColor(task.id),
   924  	}
   925  	targ := TaskArg{ID: task.id}
   926  	if task.create != nil {
   927  		sl.Stack = ctx.stack(task.create.Stk)
   928  		targ.StartG = task.create.G
   929  	}
   930  	if task.end != nil {
   931  		sl.EndStack = ctx.stack(task.end.Stk)
   932  		targ.EndG = task.end.G
   933  	}
   934  	sl.Arg = targ
   935  	ctx.emit(sl)
   936  
   937  	if task.create != nil && task.create.Type == trace.EvUserTaskCreate && task.create.Args[1] != 0 {
   938  		ctx.arrowSeq++
   939  		ctx.emit(&ViewerEvent{Name: "newTask", Phase: "s", Tid: task.create.Args[1], ID: ctx.arrowSeq, Time: ts, Pid: tasksSection})
   940  		ctx.emit(&ViewerEvent{Name: "newTask", Phase: "t", Tid: taskRow, ID: ctx.arrowSeq, Time: ts, Pid: tasksSection})
   941  	}
   942  }
   943  
   944  func (ctx *traceContext) emitRegion(s regionDesc) {
   945  	if s.Name == "" {
   946  		return
   947  	}
   948  
   949  	if !tsWithinRange(s.firstTimestamp(), ctx.startTime, ctx.endTime) &&
   950  		!tsWithinRange(s.lastTimestamp(), ctx.startTime, ctx.endTime) {
   951  		return
   952  	}
   953  
   954  	ctx.regionID++
   955  	regionID := ctx.regionID
   956  
   957  	id := s.TaskID
   958  	scopeID := fmt.Sprintf("%x", id)
   959  	name := s.Name
   960  
   961  	sl0 := &ViewerEvent{
   962  		Category: "Region",
   963  		Name:     name,
   964  		Phase:    "b",
   965  		Time:     float64(s.firstTimestamp()) / 1e3,
   966  		Tid:      s.G, // only in goroutine-oriented view
   967  		ID:       uint64(regionID),
   968  		Scope:    scopeID,
   969  		Cname:    pickTaskColor(s.TaskID),
   970  	}
   971  	if s.Start != nil {
   972  		sl0.Stack = ctx.stack(s.Start.Stk)
   973  	}
   974  	ctx.emit(sl0)
   975  
   976  	sl1 := &ViewerEvent{
   977  		Category: "Region",
   978  		Name:     name,
   979  		Phase:    "e",
   980  		Time:     float64(s.lastTimestamp()) / 1e3,
   981  		Tid:      s.G,
   982  		ID:       uint64(regionID),
   983  		Scope:    scopeID,
   984  		Cname:    pickTaskColor(s.TaskID),
   985  		Arg:      RegionArg{TaskID: s.TaskID},
   986  	}
   987  	if s.End != nil {
   988  		sl1.Stack = ctx.stack(s.End.Stk)
   989  	}
   990  	ctx.emit(sl1)
   991  }
   992  
   993  type heapCountersArg struct {
   994  	Allocated uint64
   995  	NextGC    uint64
   996  }
   997  
   998  func (ctx *traceContext) emitHeapCounters(ev *trace.Event) {
   999  	if ctx.prevHeapStats == ctx.heapStats {
  1000  		return
  1001  	}
  1002  	diff := uint64(0)
  1003  	if ctx.heapStats.nextGC > ctx.heapStats.heapAlloc {
  1004  		diff = ctx.heapStats.nextGC - ctx.heapStats.heapAlloc
  1005  	}
  1006  	if tsWithinRange(ev.Ts, ctx.startTime, ctx.endTime) {
  1007  		ctx.emit(&ViewerEvent{Name: "Heap", Phase: "C", Time: ctx.time(ev), Pid: 1, Arg: &heapCountersArg{ctx.heapStats.heapAlloc, diff}})
  1008  	}
  1009  	ctx.prevHeapStats = ctx.heapStats
  1010  }
  1011  
  1012  type goroutineCountersArg struct {
  1013  	Running   uint64
  1014  	Runnable  uint64
  1015  	GCWaiting uint64
  1016  }
  1017  
  1018  func (ctx *traceContext) emitGoroutineCounters(ev *trace.Event) {
  1019  	if ctx.prevGstates == ctx.gstates {
  1020  		return
  1021  	}
  1022  	if tsWithinRange(ev.Ts, ctx.startTime, ctx.endTime) {
  1023  		ctx.emit(&ViewerEvent{Name: "Goroutines", Phase: "C", Time: ctx.time(ev), Pid: 1, Arg: &goroutineCountersArg{uint64(ctx.gstates[gRunning]), uint64(ctx.gstates[gRunnable]), uint64(ctx.gstates[gWaitingGC])}})
  1024  	}
  1025  	ctx.prevGstates = ctx.gstates
  1026  }
  1027  
  1028  type threadCountersArg struct {
  1029  	Running   int64
  1030  	InSyscall int64
  1031  }
  1032  
  1033  func (ctx *traceContext) emitThreadCounters(ev *trace.Event) {
  1034  	if ctx.prevThreadStats == ctx.threadStats {
  1035  		return
  1036  	}
  1037  	if tsWithinRange(ev.Ts, ctx.startTime, ctx.endTime) {
  1038  		ctx.emit(&ViewerEvent{Name: "Threads", Phase: "C", Time: ctx.time(ev), Pid: 1, Arg: &threadCountersArg{
  1039  			Running:   ctx.threadStats.prunning,
  1040  			InSyscall: ctx.threadStats.insyscall}})
  1041  	}
  1042  	ctx.prevThreadStats = ctx.threadStats
  1043  }
  1044  
  1045  func (ctx *traceContext) emitInstant(ev *trace.Event, name, category string) {
  1046  	if !tsWithinRange(ev.Ts, ctx.startTime, ctx.endTime) {
  1047  		return
  1048  	}
  1049  
  1050  	cname := ""
  1051  	if ctx.mode&modeTaskOriented != 0 {
  1052  		taskID, isUserAnnotation := isUserAnnotationEvent(ev)
  1053  
  1054  		show := false
  1055  		for _, task := range ctx.tasks {
  1056  			if isUserAnnotation && task.id == taskID || task.overlappingInstant(ev) {
  1057  				show = true
  1058  				break
  1059  			}
  1060  		}
  1061  		// grey out or skip if non-overlapping instant.
  1062  		if !show {
  1063  			if isUserAnnotation {
  1064  				return // don't display unrelated user annotation events.
  1065  			}
  1066  			cname = colorLightGrey
  1067  		}
  1068  	}
  1069  	var arg interface{}
  1070  	if ev.Type == trace.EvProcStart {
  1071  		type Arg struct {
  1072  			ThreadID uint64
  1073  		}
  1074  		arg = &Arg{ev.Args[0]}
  1075  	}
  1076  	ctx.emit(&ViewerEvent{
  1077  		Name:     name,
  1078  		Category: category,
  1079  		Phase:    "I",
  1080  		Scope:    "t",
  1081  		Time:     ctx.time(ev),
  1082  		Tid:      ctx.proc(ev),
  1083  		Stack:    ctx.stack(ev.Stk),
  1084  		Cname:    cname,
  1085  		Arg:      arg})
  1086  }
  1087  
  1088  func (ctx *traceContext) emitArrow(ev *trace.Event, name string) {
  1089  	if ev.Link == nil {
  1090  		// The other end of the arrow is not captured in the trace.
  1091  		// For example, a goroutine was unblocked but was not scheduled before trace stop.
  1092  		return
  1093  	}
  1094  	if ctx.mode&modeGoroutineOriented != 0 && (!ctx.gs[ev.Link.G] || ev.Link.Ts < ctx.startTime || ev.Link.Ts > ctx.endTime) {
  1095  		return
  1096  	}
  1097  
  1098  	if ev.P == trace.NetpollP || ev.P == trace.TimerP || ev.P == trace.SyscallP {
  1099  		// Trace-viewer discards arrows if they don't start/end inside of a slice or instant.
  1100  		// So emit a fake instant at the start of the arrow.
  1101  		ctx.emitInstant(&trace.Event{P: ev.P, Ts: ev.Ts}, "unblock", "")
  1102  	}
  1103  
  1104  	color := ""
  1105  	if ctx.mode&modeTaskOriented != 0 {
  1106  		overlapping := false
  1107  		// skip non-overlapping arrows.
  1108  		for _, task := range ctx.tasks {
  1109  			if _, overlapped := task.overlappingDuration(ev); overlapped {
  1110  				overlapping = true
  1111  				break
  1112  			}
  1113  		}
  1114  		if !overlapping {
  1115  			return
  1116  		}
  1117  	}
  1118  
  1119  	ctx.arrowSeq++
  1120  	ctx.emit(&ViewerEvent{Name: name, Phase: "s", Tid: ctx.proc(ev), ID: ctx.arrowSeq, Time: ctx.time(ev), Stack: ctx.stack(ev.Stk), Cname: color})
  1121  	ctx.emit(&ViewerEvent{Name: name, Phase: "t", Tid: ctx.proc(ev.Link), ID: ctx.arrowSeq, Time: ctx.time(ev.Link), Cname: color})
  1122  }
  1123  
  1124  func (ctx *traceContext) stack(stk []*trace.Frame) int {
  1125  	return ctx.buildBranch(ctx.frameTree, stk)
  1126  }
  1127  
  1128  // buildBranch builds one branch in the prefix tree rooted at ctx.frameTree.
  1129  func (ctx *traceContext) buildBranch(parent frameNode, stk []*trace.Frame) int {
  1130  	if len(stk) == 0 {
  1131  		return parent.id
  1132  	}
  1133  	last := len(stk) - 1
  1134  	frame := stk[last]
  1135  	stk = stk[:last]
  1136  
  1137  	node, ok := parent.children[frame.PC]
  1138  	if !ok {
  1139  		ctx.frameSeq++
  1140  		node.id = ctx.frameSeq
  1141  		node.children = make(map[uint64]frameNode)
  1142  		parent.children[frame.PC] = node
  1143  		ctx.consumer.consumeViewerFrame(strconv.Itoa(node.id), ViewerFrame{fmt.Sprintf("%v:%v", frame.Fn, frame.Line), parent.id})
  1144  	}
  1145  	return ctx.buildBranch(node, stk)
  1146  }
  1147  
  1148  func isSystemGoroutine(entryFn string) bool {
  1149  	// This mimics runtime.isSystemGoroutine as closely as
  1150  	// possible.
  1151  	return entryFn != "runtime.main" && strings.HasPrefix(entryFn, "runtime.")
  1152  }
  1153  
  1154  // firstTimestamp returns the timestamp of the first event record.
  1155  func firstTimestamp() int64 {
  1156  	res, _ := parseTrace()
  1157  	if len(res.Events) > 0 {
  1158  		return res.Events[0].Ts
  1159  	}
  1160  	return 0
  1161  }
  1162  
  1163  // lastTimestamp returns the timestamp of the last event record.
  1164  func lastTimestamp() int64 {
  1165  	res, _ := parseTrace()
  1166  	if n := len(res.Events); n > 1 {
  1167  		return res.Events[n-1].Ts
  1168  	}
  1169  	return 0
  1170  }
  1171  
  1172  type jsonWriter struct {
  1173  	w   io.Writer
  1174  	enc *json.Encoder
  1175  }
  1176  
  1177  func viewerDataTraceConsumer(w io.Writer, start, end int64) traceConsumer {
  1178  	frames := make(map[string]ViewerFrame)
  1179  	enc := json.NewEncoder(w)
  1180  	written := 0
  1181  	index := int64(-1)
  1182  
  1183  	io.WriteString(w, "{")
  1184  	return traceConsumer{
  1185  		consumeTimeUnit: func(unit string) {
  1186  			io.WriteString(w, `"displayTimeUnit":`)
  1187  			enc.Encode(unit)
  1188  			io.WriteString(w, ",")
  1189  		},
  1190  		consumeViewerEvent: func(v *ViewerEvent, required bool) {
  1191  			index++
  1192  			if !required && (index < start || index > end) {
  1193  				// not in the range. Skip!
  1194  				return
  1195  			}
  1196  			if written == 0 {
  1197  				io.WriteString(w, `"traceEvents": [`)
  1198  			}
  1199  			if written > 0 {
  1200  				io.WriteString(w, ",")
  1201  			}
  1202  			enc.Encode(v)
  1203  			// TODO: get rid of the extra \n inserted by enc.Encode.
  1204  			// Same should be applied to splittingTraceConsumer.
  1205  			written++
  1206  		},
  1207  		consumeViewerFrame: func(k string, v ViewerFrame) {
  1208  			frames[k] = v
  1209  		},
  1210  		flush: func() {
  1211  			io.WriteString(w, `], "stackFrames":`)
  1212  			enc.Encode(frames)
  1213  			io.WriteString(w, `}`)
  1214  		},
  1215  	}
  1216  }
  1217  
  1218  // Mapping from more reasonable color names to the reserved color names in
  1219  // https://github.com/catapult-project/catapult/blob/master/tracing/tracing/base/color_scheme.html#L50
  1220  // The chrome trace viewer allows only those as cname values.
  1221  const (
  1222  	colorLightMauve     = "thread_state_uninterruptible" // 182, 125, 143
  1223  	colorOrange         = "thread_state_iowait"          // 255, 140, 0
  1224  	colorSeafoamGreen   = "thread_state_running"         // 126, 200, 148
  1225  	colorVistaBlue      = "thread_state_runnable"        // 133, 160, 210
  1226  	colorTan            = "thread_state_unknown"         // 199, 155, 125
  1227  	colorIrisBlue       = "background_memory_dump"       // 0, 180, 180
  1228  	colorMidnightBlue   = "light_memory_dump"            // 0, 0, 180
  1229  	colorDeepMagenta    = "detailed_memory_dump"         // 180, 0, 180
  1230  	colorBlue           = "vsync_highlight_color"        // 0, 0, 255
  1231  	colorGrey           = "generic_work"                 // 125, 125, 125
  1232  	colorGreen          = "good"                         // 0, 125, 0
  1233  	colorDarkGoldenrod  = "bad"                          // 180, 125, 0
  1234  	colorPeach          = "terrible"                     // 180, 0, 0
  1235  	colorBlack          = "black"                        // 0, 0, 0
  1236  	colorLightGrey      = "grey"                         // 221, 221, 221
  1237  	colorWhite          = "white"                        // 255, 255, 255
  1238  	colorYellow         = "yellow"                       // 255, 255, 0
  1239  	colorOlive          = "olive"                        // 100, 100, 0
  1240  	colorCornflowerBlue = "rail_response"                // 67, 135, 253
  1241  	colorSunsetOrange   = "rail_animation"               // 244, 74, 63
  1242  	colorTangerine      = "rail_idle"                    // 238, 142, 0
  1243  	colorShamrockGreen  = "rail_load"                    // 13, 168, 97
  1244  	colorGreenishYellow = "startup"                      // 230, 230, 0
  1245  	colorDarkGrey       = "heap_dump_stack_frame"        // 128, 128, 128
  1246  	colorTawny          = "heap_dump_child_node_arrow"   // 204, 102, 0
  1247  	colorLemon          = "cq_build_running"             // 255, 255, 119
  1248  	colorLime           = "cq_build_passed"              // 153, 238, 102
  1249  	colorPink           = "cq_build_failed"              // 238, 136, 136
  1250  	colorSilver         = "cq_build_abandoned"           // 187, 187, 187
  1251  	colorManzGreen      = "cq_build_attempt_runnig"      // 222, 222, 75
  1252  	colorKellyGreen     = "cq_build_attempt_passed"      // 108, 218, 35
  1253  	colorAnotherGrey    = "cq_build_attempt_failed"      // 187, 187, 187
  1254  )
  1255  
  1256  var colorForTask = []string{
  1257  	colorLightMauve,
  1258  	colorOrange,
  1259  	colorSeafoamGreen,
  1260  	colorVistaBlue,
  1261  	colorTan,
  1262  	colorMidnightBlue,
  1263  	colorIrisBlue,
  1264  	colorDeepMagenta,
  1265  	colorGreen,
  1266  	colorDarkGoldenrod,
  1267  	colorPeach,
  1268  	colorOlive,
  1269  	colorCornflowerBlue,
  1270  	colorSunsetOrange,
  1271  	colorTangerine,
  1272  	colorShamrockGreen,
  1273  	colorTawny,
  1274  	colorLemon,
  1275  	colorLime,
  1276  	colorPink,
  1277  	colorSilver,
  1278  	colorManzGreen,
  1279  	colorKellyGreen,
  1280  }
  1281  
  1282  func pickTaskColor(id uint64) string {
  1283  	idx := id % uint64(len(colorForTask))
  1284  	return colorForTask[idx]
  1285  }