Collect useful resource information of each executed process in soong_ui.

Collect the resource information of each executed process in soong_ui
for metrics analysis.

Bug: b/169453825
Test: m nothing; "lunch 1" && m
Change-Id: I8c7fe019111921c4c59174d133b85439ec825885

ui/build/exec.go

@@ -66,8 +66,11 @@ func (c *Cmd) prepare() {
 }
 
 func (c *Cmd) report() {
-	if c.Cmd.ProcessState != nil {
+	if state := c.Cmd.ProcessState; state != nil {
-		rusage := c.Cmd.ProcessState.SysUsage().(*syscall.Rusage)
+		if c.ctx.Metrics != nil {
+			c.ctx.Metrics.EventTracer.AddProcResInfo(c.name, state)
+		}
+		rusage := state.SysUsage().(*syscall.Rusage)
 		c.ctx.Verbosef("%q finished with exit code %d (%s real, %s user, %s system, %dMB maxrss)",
 			c.name, c.Cmd.ProcessState.ExitCode(),
 			time.Since(c.started).Round(time.Millisecond),

ui/metrics/event.go

@@ -15,6 +15,8 @@
 package metrics
 
 import (
+	"os"
+	"syscall"
 	"time"
 
 	"android/soong/ui/metrics/metrics_proto"
@@ -31,11 +33,15 @@ type event struct {
 
 	// the time that the event started to occur.
 	start time.Time
+
+	// The list of process resource information that was executed
+	procResInfo []*soong_metrics_proto.ProcessResourceInfo
 }
 
 type EventTracer interface {
 	Begin(name, desc string, thread tracer.Thread)
 	End(thread tracer.Thread) soong_metrics_proto.PerfInfo
+	AddProcResInfo(string, *os.ProcessState)
 }
 
 type eventTracerImpl struct {
@@ -48,6 +54,34 @@ func now() time.Time {
 	return time.Now()
 }
 
+// AddProcResInfo adds information on an executed process such as max resident set memory
+// and the number of voluntary context switches.
+func (t *eventTracerImpl) AddProcResInfo(name string, state *os.ProcessState) {
+	if len(t.activeEvents) < 1 {
+		return
+	}
+
+	rusage := state.SysUsage().(*syscall.Rusage)
+	// The implementation of the metrics system is a stacked based system. The steps of the
+	// build system in the UI layer is sequential so the Begin function is invoked when a
+	// function (or scoped code) is invoked. That is translated to a new event which is added
+	// at the end of the activeEvents array. When the invoking function is completed, End is
+	// invoked which is a pop operation from activeEvents.
+	curEvent := &t.activeEvents[len(t.activeEvents)-1]
+	curEvent.procResInfo = append(curEvent.procResInfo, &soong_metrics_proto.ProcessResourceInfo{
+		Name:             proto.String(name),
+		UserTimeMicros:   proto.Uint64(uint64(rusage.Utime.Usec)),
+		SystemTimeMicros: proto.Uint64(uint64(rusage.Stime.Usec)),
+		MinorPageFaults:  proto.Uint64(uint64(rusage.Minflt)),
+		MajorPageFaults:  proto.Uint64(uint64(rusage.Majflt)),
+		// ru_inblock and ru_oublock are measured in blocks of 512 bytes.
+		IoInputKb:                  proto.Uint64(uint64(rusage.Inblock / 2)),
+		IoOutputKb:                 proto.Uint64(uint64(rusage.Oublock / 2)),
+		VoluntaryContextSwitches:   proto.Uint64(uint64(rusage.Nvcsw)),
+		InvoluntaryContextSwitches: proto.Uint64(uint64(rusage.Nivcsw)),
+	})
+}
+
 func (t *eventTracerImpl) Begin(name, desc string, _ tracer.Thread) {
 	t.activeEvents = append(t.activeEvents, event{name: name, desc: desc, start: _now()})
 }
@@ -65,5 +99,6 @@ func (t *eventTracerImpl) End(tracer.Thread) soong_metrics_proto.PerfInfo {
 		Name:                  proto.String(lastEvent.name),
 		StartTime:             proto.Uint64(uint64(lastEvent.start.UnixNano())),
 		RealTime:              proto.Uint64(realTime),
+		ProcessesResourceInfo: lastEvent.procResInfo,
 	}
 }