1// Copyright 2018 Google Inc. All Rights Reserved. 2// 3// Licensed under the Apache License, Version 2.0 (the "License"); 4// you may not use this file except in compliance with the License. 5// You may obtain a copy of the License at 6// 7// http://www.apache.org/licenses/LICENSE-2.0 8// 9// Unless required by applicable law or agreed to in writing, software 10// distributed under the License is distributed on an "AS IS" BASIS, 11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12// See the License for the specific language governing permissions and 13// limitations under the License. 14 15package metrics 16 17// This file contains the functionality to represent a build event in respect 18// to the metric system. A build event corresponds to a block of scoped code 19// that contains a "Begin()" and immediately followed by "defer End()" trace. 20// When defined, the duration of the scoped code is measure along with other 21// performance measurements such as memory. 22// 23// As explained in the metrics package, the metrics system is a stacked based 24// system since the collected metrics is considered to be topline metrics. 25// The steps of the build system in the UI layer is sequential. Hence, the 26// functionality defined below follows the stack data structure operations. 27 28import ( 29 "os" 30 "syscall" 31 "time" 32 33 "android/soong/ui/metrics/metrics_proto" 34 "android/soong/ui/tracer" 35 36 "github.com/golang/protobuf/proto" 37) 38 39// _now wraps the time.Now() function. _now is declared for unit testing purpose. 40var _now = func() time.Time { 41 return time.Now() 42} 43 44// event holds the performance metrics data of a single build event. 45type event struct { 46 // The event name (mostly used for grouping a set of events) 47 name string 48 49 // The description of the event (used to uniquely identify an event 50 // for metrics analysis). 51 desc string 52 53 // The time that the event started to occur. 54 start time.Time 55 56 // The list of process resource information that was executed. 57 procResInfo []*soong_metrics_proto.ProcessResourceInfo 58} 59 60// newEvent returns an event with start populated with the now time. 61func newEvent(name, desc string) *event { 62 return &event{ 63 name: name, 64 desc: desc, 65 start: _now(), 66 } 67} 68 69func (e event) perfInfo() soong_metrics_proto.PerfInfo { 70 realTime := uint64(_now().Sub(e.start).Nanoseconds()) 71 return soong_metrics_proto.PerfInfo{ 72 Desc: proto.String(e.desc), 73 Name: proto.String(e.name), 74 StartTime: proto.Uint64(uint64(e.start.UnixNano())), 75 RealTime: proto.Uint64(realTime), 76 ProcessesResourceInfo: e.procResInfo, 77 } 78} 79 80// EventTracer is an array of events that provides functionality to trace a 81// block of code on time and performance. The End call expects the Begin is 82// invoked, otherwise panic is raised. 83type EventTracer []*event 84 85// empty returns true if there are no pending events. 86func (t *EventTracer) empty() bool { 87 return len(*t) == 0 88} 89 90// lastIndex returns the index of the last element of events. 91func (t *EventTracer) lastIndex() int { 92 return len(*t) - 1 93} 94 95// peek returns the active build event. 96func (t *EventTracer) peek() *event { 97 return (*t)[t.lastIndex()] 98} 99 100// push adds the active build event in the stack. 101func (t *EventTracer) push(e *event) { 102 *t = append(*t, e) 103} 104 105// pop removes the active event from the stack since the event has completed. 106// A panic is raised if there are no pending events. 107func (t *EventTracer) pop() *event { 108 if t.empty() { 109 panic("Internal error: No pending events") 110 } 111 e := (*t)[t.lastIndex()] 112 *t = (*t)[:t.lastIndex()] 113 return e 114} 115 116// AddProcResInfo adds information on an executed process such as max resident 117// set memory and the number of voluntary context switches. 118func (t *EventTracer) AddProcResInfo(name string, state *os.ProcessState) { 119 if t.empty() { 120 return 121 } 122 123 rusage := state.SysUsage().(*syscall.Rusage) 124 e := t.peek() 125 e.procResInfo = append(e.procResInfo, &soong_metrics_proto.ProcessResourceInfo{ 126 Name: proto.String(name), 127 UserTimeMicros: proto.Uint64(uint64(rusage.Utime.Usec)), 128 SystemTimeMicros: proto.Uint64(uint64(rusage.Stime.Usec)), 129 MinorPageFaults: proto.Uint64(uint64(rusage.Minflt)), 130 MajorPageFaults: proto.Uint64(uint64(rusage.Majflt)), 131 // ru_inblock and ru_oublock are measured in blocks of 512 bytes. 132 IoInputKb: proto.Uint64(uint64(rusage.Inblock / 2)), 133 IoOutputKb: proto.Uint64(uint64(rusage.Oublock / 2)), 134 VoluntaryContextSwitches: proto.Uint64(uint64(rusage.Nvcsw)), 135 InvoluntaryContextSwitches: proto.Uint64(uint64(rusage.Nivcsw)), 136 }) 137} 138 139// Begin starts tracing the event. 140func (t *EventTracer) Begin(name, desc string, _ tracer.Thread) { 141 t.push(newEvent(name, desc)) 142} 143 144// End performs post calculations such as duration of the event, aggregates 145// the collected performance information into PerfInfo protobuf message. 146func (t *EventTracer) End(tracer.Thread) soong_metrics_proto.PerfInfo { 147 return t.pop().perfInfo() 148} 149