cmd/trace: annotation proc start/stop with thread and proc always

In the proc view, the thread ID is useful. In the thread view, the proc
ID is useful. Add both in both cases forever more.

Change-Id: I9cb7bd67a21ee17d865c25d73b2049b3da7aefbc
Reviewed-on: https://go-review.googlesource.com/c/go/+/720402
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Auto-Submit: Michael Knyszek <mknyszek@google.com>

src/cmd/trace/procgen.go

@@ -143,6 +143,13 @@ func (g *procGenerator) ProcTransition(ctx *traceContext, ev *trace.Event) {
 	viewerEv := traceviewer.InstantEvent{
 		Resource: uint64(proc),
 		Stack:    ctx.Stack(viewerFrames(ev.Stack())),
+
+		// Annotate with the thread and proc. The proc is redundant, but this is to
+		// stay consistent with the thread view, where it's useful information.
+		Arg: format.SchedCtxArg{
+			ProcID:   uint64(st.Resource.Proc()),
+			ThreadID: uint64(ev.Thread()),
+		},
 	}
 
 	from, to := st.Proc()
@@ -156,7 +163,6 @@ func (g *procGenerator) ProcTransition(ctx *traceContext, ev *trace.Event) {
 			start = ctx.startTime
 		}
 		viewerEv.Name = "proc start"
-		viewerEv.Arg = format.ThreadIDArg{ThreadID: uint64(ev.Thread())}
 		viewerEv.Ts = ctx.elapsed(start)
 		ctx.IncThreadStateCount(ctx.elapsed(start), traceviewer.ThreadStateRunning, 1)
 	}

src/cmd/trace/threadgen.go

@@ -138,14 +138,17 @@ func (g *threadGenerator) ProcTransition(ctx *traceContext, ev *trace.Event) {
 		}
 	}
 
-	type procArg struct {
-		Proc uint64 `json:"proc,omitempty"`
-	}
 	st := ev.StateTransition()
 	viewerEv := traceviewer.InstantEvent{
 		Resource: uint64(ev.Thread()),
 		Stack:    ctx.Stack(viewerFrames(ev.Stack())),
-		Arg:      procArg{Proc: uint64(st.Resource.Proc())},
+
+		// Annotate with the thread and proc. The thread is redundant, but this is to
+		// stay consistent with the proc view.
+		Arg: format.SchedCtxArg{
+			ProcID:   uint64(st.Resource.Proc()),
+			ThreadID: uint64(ev.Thread()),
+		},
 	}
 
 	from, to := st.Proc()
@@ -159,7 +162,6 @@ func (g *threadGenerator) ProcTransition(ctx *traceContext, ev *trace.Event) {
 			start = ctx.startTime
 		}
 		viewerEv.Name = "proc start"
-		viewerEv.Arg = format.ThreadIDArg{ThreadID: uint64(ev.Thread())}
 		viewerEv.Ts = ctx.elapsed(start)
 		// TODO(mknyszek): We don't have a state machine for threads, so approximate
 		// running threads with running Ps.

src/internal/trace/traceviewer/format/format.go

@@ -74,6 +74,7 @@ type ThreadCountersArg struct {
 	InSyscall int64
 }
 
-type ThreadIDArg struct {
-	ThreadID uint64
+type SchedCtxArg struct {
+	ThreadID uint64 `json:"thread,omitempty"`
+	ProcID   uint64 `json:"proc,omitempty"`
 }