b0.Event("ProcStatus", trace.ProcID(1), go122.ProcRunning)
	b0.Event("GoStatus", trace.GoID(1), trace.ThreadID(0), go122.GoSyscall)
	b0.Event("GoSyscallEndBlocked")

	// A running goroutine stole P0 at the generation boundary.
	b1 := g.Batch(trace.ThreadID(1), 0)
	b1.Event("ProcStatus", trace.ProcID(2), go122.ProcRunning)
	b1.Event("GoStatus", trace.GoID(2), trace.ThreadID(1), go122.GoRunning)

			g.threads[ev.Thread()] = struct{}{}
		}
	}

	st := ev.StateTransition()
	goID := st.Resource.Goroutine()

	// If we haven't seen this goroutine before, create a new
	// gState for it.
	gs, ok := g.gStates[goID]
	if !ok {
		gs = newGState[trace.ThreadID](goID)
		g.gStates[goID] = gs
	}
	// If we haven't already named this goroutine, try to name it.
	gs.augmentName(st.Stack)

// If the id string is empty, returns nil without an error.
func pprofMatchingGoroutines(name string, t *parsedTrace) (map[trace.GoID][]interval, error) {
	res := make(map[trace.GoID][]interval)
	for _, g := range t.summary.Goroutines {
		if name != "" && g.Name != name {
			continue
		}
		endTime := g.EndTime
		if g.EndTime == 0 {

// If an exit hook invokes exit in another goroutine, that exit will block.
func Run(code int) {
	for !locked.CompareAndSwap(0, 1) {
		if Goid() == runGoid.Load() {
			Throw("exit hook invoked exit")
		}
		Gosched()
	}
	defer locked.Store(0)
	runGoid.Store(Goid())
	defer runGoid.Store(0)

	defer func() {
		if e := recover(); e != nil {
			Throw("exit hook invoked panic")
		}
	}()

// writeGoStatus emits a GoStatus event as well as any active ranges on the goroutine.
func (w traceWriter) writeGoStatus(goid uint64, mid int64, status traceGoStatus, markAssist bool, stackID uint64) traceWriter {
	// The status should never be bad. Some invariant must have been violated.
	if status == traceGoBad {
		print("runtime: goid=", goid, "\n")
		throw("attempted to trace a bad status for a goroutine")
	}

	// Trace the status.

	// A goroutine gets created on a running P, then starts running.
	b0 := g1.Batch(trace.ThreadID(0), 0)
	b0.Event("ProcStatus", trace.ProcID(0), go122.ProcRunning)
	b0.Event("GoCreate", trace.GoID(5), testgen.NoStack, testgen.NoStack)
	b0.Event("GoStart", trace.GoID(5), testgen.Seq(1))
	b0.Event("GoStop", "whatever", testgen.NoStack)

	b0.Event("GoStatus", trace.GoID(1), trace.ThreadID(0), go122.GoRunning)
	b0.Event("GoSyscallBegin", testgen.Seq(1), testgen.NoStack)
	b0.Event("ProcStart", trace.ProcID(1), testgen.Seq(1))
	b0.Event("GoSyscallEndBlocked")

	// A running goroutine steals proc 0.
	b1 := g.Batch(trace.ThreadID(1), 0)
	b1.Event("ProcStatus", trace.ProcID(2), go122.ProcRunning)
	b1.Event("GoStatus", trace.GoID(2), trace.ThreadID(1), go122.GoRunning)

	b0 := g.Batch(trace.ThreadID(0), 0)
	b0.Event("GoCreateSyscall", trace.GoID(4))
	b0.Event("GoSyscallEndBlocked")
	b0.Event("ProcStatus", trace.ProcID(0), go122.ProcIdle)
	b0.Event("ProcStart", trace.ProcID(0), testgen.Seq(1))
	b0.Event("GoStatus", trace.GoID(4), trace.NoThread, go122.GoRunnable)
	b0.Event("GoStart", trace.GoID(4), testgen.Seq(1))
	b0.Event("GoSyscallBegin", testgen.Seq(2), testgen.NoStack)

	b0.Event("GoStatus", trace.GoID(1), trace.ThreadID(0), go122.GoRunning)
	b0.Event("GoSyscallBegin", testgen.Seq(1), testgen.NoStack)
	b0.Event("GoSyscallEndBlocked")

	// A running goroutine steals proc 0.
	b1 := g.Batch(trace.ThreadID(1), 0)
	b1.Event("ProcStatus", trace.ProcID(2), go122.ProcRunning)
	b1.Event("GoStatus", trace.GoID(2), trace.ThreadID(1), go122.GoRunning)

}

func gen(t *testgen.Trace) {
	g := t.Generation(1)

	// One goroutine is exiting with a syscall. It already
	// acquired a new P.
	b0 := g.Batch(trace.ThreadID(0), 0)
	b0.Event("GoStatus", trace.GoID(1), trace.ThreadID(0), go122.GoSyscall)
	b0.Event("ProcStatus", trace.ProcID(1), go122.ProcIdle)
	b0.Event("ProcStart", trace.ProcID(1), testgen.Seq(1))
	b0.Event("GoSyscallEndBlocked")