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UPDATE FROM二○一五年十月三十○日阿卡插播实现比单线程实现较慢
基于罗兰库恩Awnser：
阿卡流是使用异步消息参与者之间传递给 实现流处理阶段。通过异步边界传递数据会产生以下开销：您的 计算似乎只需要大约160ns（源自 单线程度量），而流式传输解决方案每个元素需要大约1μs，其中 占主导地位消息传递。
另一个误解是，说“流”意味着并行：在 代码都计算在一个单一的演员（地图 阶段）顺序运行，因此没有任何好处，可以预计在原始 单线程解决方案。
为了从阿卡提供的并行性收益流，你 需要有多个处理阶段，每个执行的每个元素
1μs的任务，也看到了文档。
我做了一些更改。我的代码现在看起来像：
object MultiThread {
implicit val actorSystem = ActorSystem("Sys")
implicit val materializer = ActorMaterializer()
var counter = 0
var oldProgess = 0
//RunnableFlow: in -> flow -> sink
val in = Source(() => Iterator.continually((1254785478l, "name", 48, 23.09f)))
val flow = Flow[(Long, String, Int, Float)].map(p => SharedFunctions.transform2(SharedFunctions.transform(p)))
val tupleToEvent = Flow[(Long, String, Int, Float)].map(SharedFunctions.transform)
val eventToFactorial = Flow[Event].map(SharedFunctions.transform2)
val eventChef: Flow[(Long, String, Int, Float), Int, Unit] = Flow() { implicit builder =>
import FlowGraph.Implicits._
val dispatchTuple = builder.add(Balance[(Long, String, Int, Float)](4))
val mergeEvents = builder.add(Merge[Int](4))
dispatchTuple.out(0) ~> tupleToEvent ~> eventToFactorial ~> mergeEvents.in(0)
dispatchTuple.out(1) ~> tupleToEvent ~> eventToFactorial ~> mergeEvents.in(1)
dispatchTuple.out(2) ~> tupleToEvent ~> eventToFactorial ~> mergeEvents.in(2)
dispatchTuple.out(3) ~> tupleToEvent ~> eventToFactorial ~> mergeEvents.in(3)
(dispatchTuple.in, mergeEvents.out)
}
val sink = Sink.foreach[Int]{
v => counter += 1
oldProgess = SharedFunctions.printProgress(oldProgess, SharedFunctions.maxEventCount, counter,
DateTime.now.getMillis - SharedFunctions.startTime.getMillis)
if(counter == SharedFunctions.maxEventCount) endAkka()
}
def endAkka() = {
val duration = new Duration(SharedFunctions.startTime, DateTime.now)
println("Time: " + duration.getMillis + " || Data: " + counter)
actorSystem.shutdown
actorSystem.awaitTermination
System.exit(-1)
}
def main(args: Array[String]) {
println("MultiThread started: " + SharedFunctions.startTime)
in.via(flow).runWith(sink)
// in.via(eventChef).runWith(sink)
}
}
我不知道，如果我得到的东西完全错误的，但仍然是我与阿卡流的实现是慢得多（现在更慢如前），但我发现了什么是：如果我例如通过做一些分工来增加工作量，用阿卡流实施会变得更快。所以，如果我把它做对了（否则纠正我），我的例子似乎有太多的开销。所以如果代码需要做大量的工作，你只能从阿卡流中获益呢？
我是比较新的两阶&阿卡 - 流。我写了一个小测试项目，创建一些事件，直到一个计数器达到特定的数字。对于每个事件，正在计算事件的一个字段的阶乘。我实施了两次。一次使用akka-stream，一次不使用akka-stream（单线程），并比较运行时间。
我没想到：当我创建单个事件时，两个程序的运行时间几乎相同。但是如果我创建了70,000,000个事件，没有AKK流的实现要快得多。这里是我的结果（以下数据是基于24次测量）：
- 单事件，而不阿卡流：403（+ - 2）MS
与单事件阿卡流：444（+ -13）ms的
70Mio事件而不阿卡流：11778（+ -70）MS与
- 70Mio事件阿卡回笼：75424（+ - 2959）MS
所以我的问题是：发生了什么事？为什么我的akka-stream实现比较慢？
这里我的代码：
实现与阿卡
object MultiThread {
implicit val actorSystem = ActorSystem("Sys")
implicit val materializer = ActorMaterializer()
var counter = 0
var oldProgess = 0
//RunnableFlow: in -> flow -> sink
val in = Source(() => Iterator.continually((1254785478l, "name", 48, 23.09f)))
val flow = Flow[(Long, String, Int, Float)].map(p => SharedFunctions.transform2(SharedFunctions.transform(p)))
val sink = Sink.foreach[Int]{
v => counter += 1
oldProgess = SharedFunctions.printProgress(oldProgess, SharedFunctions.maxEventCount, counter,
DateTime.now.getMillis - SharedFunctions.startTime.getMillis)
if(counter == SharedFunctions.maxEventCount) endAkka()
}
def endAkka() = {
val duration = new Duration(SharedFunctions.startTime, DateTime.now)
println("Time: " + duration.getMillis + " || Data: " + counter)
actorSystem.shutdown
actorSystem.awaitTermination
System.exit(-1)
}
def main(args: Array[String]) {
import scala.concurrent.ExecutionContext.Implicits.global
println("MultiThread started: " + SharedFunctions.startTime)
in.via(flow).runWith(sink).onComplete(_ => endAkka())
}
}
实现无阿卡
对象SingleThread {
def main(args: Array[String]) {
println("SingleThread started at: " + SharedFunctions.startTime)
println("0%")
val i = createEvent(0)
val duration = new Duration(SharedFunctions.startTime, DateTime.now());
println("Time: " + duration.getMillis + " || Data: " + i)
}
def createEventWorker(oldProgress: Int, count: Int, randDate: Long, name: String, age: Int, myFloat: Float): Int = {
if (count == SharedFunctions.maxEventCount) count
else {
val e = SharedFunctions.transform((randDate, name, age, myFloat))
SharedFunctions.transform2(e)
val p = SharedFunctions.printProgress(oldProgress, SharedFunctions.maxEventCount, count,
DateTime.now.getMillis - SharedFunctions.startTime.getMillis)
createEventWorker(p, count + 1, 1254785478l, "name", 48, 23.09f)
}
}
def createEvent(count: Int): Int = {
createEventWorker(0, count, 1254785478l, "name", 48, 23.09f)
}
}
SharedFunctions
object SharedFunctions {
val maxEventCount = 70000000
val startTime = DateTime.now
def transform(t : (Long, String, Int, Float)) : Event = new Event(t._1 ,t._2,t._3,t._4)
def transform2(e : Event) : Int = factorial(e.getAgeYrs)
def calculatePercentage(totalValue: Long, currentValue: Long) = Math.round((currentValue * 100)/totalValue)
def printProgress(oldProgress : Int, fileSize: Long, currentSize: Int, t: Long) = {
val cProgress = calculatePercentage(fileSize, currentSize)
if (oldProgress != cProgress) println(s"$oldProgress% | $t ms")
cProgress
}
private def factorialWorker(n1: Int, n2: Int): Int = {
if (n1 == 0) n2
else factorialWorker(n1 -1, n2*n1)
}
def factorial (n : Int): Int = {
factorialWorker(n, 1)
}
}
执行事件
/**
* Autogenerated by Avro
*
* DO NOT EDIT DIRECTLY
*/
@SuppressWarnings("all")
@org.apache.avro.specific.AvroGenerated
public class Event extends org.apache.avro.specific.SpecificRecordBase implements org.apache.avro.specific.SpecificRecord {
public static final org.apache.avro.Schema SCHEMA$ = new org.apache.avro.Schema.Parser().parse("{\"type\":\"record\",\"name\":\"Event\",\"namespace\":\"week2P2\",\"fields\":[{\"name\":\"timestampMS\",\"type\":\"long\"},{\"name\":\"name\",\"type\":\"string\"},{\"name\":\"ageYrs\",\"type\":\"int\"},{\"name\":\"sizeCm\",\"type\":\"float\"}]}");
public static org.apache.avro.Schema getClassSchema() { return SCHEMA$; }
@Deprecated public long timestampMS;
@Deprecated public CharSequence name;
@Deprecated public int ageYrs;
@Deprecated public float sizeCm;
/**
* Default constructor. Note that this does not initialize fields
* to their default values from the schema. If that is desired then
* one should use <code>newBuilder()</code>.
*/
public Event() {}
/**
* All-args constructor.
*/
public Event(Long timestampMS, CharSequence name, Integer ageYrs, Float sizeCm) {
this.timestampMS = timestampMS;
this.name = name;
this.ageYrs = ageYrs;
this.sizeCm = sizeCm;
}
public org.apache.avro.Schema getSchema() { return SCHEMA$; }
// Used by DatumWriter. Applications should not call.
public Object get(int field$) {
switch (field$) {
case 0: return timestampMS;
case 1: return name;
case 2: return ageYrs;
case 3: return sizeCm;
default: throw new org.apache.avro.AvroRuntimeException("Bad index");
}
}
// Used by DatumReader. Applications should not call.
@SuppressWarnings(value="unchecked")
public void put(int field$, Object value$) {
switch (field$) {
case 0: timestampMS = (Long)value$; break;
case 1: name = (CharSequence)value$; break;
case 2: ageYrs = (Integer)value$; break;
case 3: sizeCm = (Float)value$; break;
default: throw new org.apache.avro.AvroRuntimeException("Bad index");
}
}
/**
* Gets the value of the 'timestampMS' field.
*/
public Long getTimestampMS() {
return timestampMS;
}
/**
* Sets the value of the 'timestampMS' field.
* @param value the value to set.
*/
public void setTimestampMS(Long value) {
this.timestampMS = value;
}
/**
* Gets the value of the 'name' field.
*/
public CharSequence getName() {
return name;
}
/**
* Sets the value of the 'name' field.
* @param value the value to set.
*/
public void setName(CharSequence value) {
this.name = value;
}
/**
* Gets the value of the 'ageYrs' field.
*/
public Integer getAgeYrs() {
return ageYrs;
}
/**
* Sets the value of the 'ageYrs' field.
* @param value the value to set.
*/
public void setAgeYrs(Integer value) {
this.ageYrs = value;
}
/**
* Gets the value of the 'sizeCm' field.
*/
public Float getSizeCm() {
return sizeCm;
}
/**
* Sets the value of the 'sizeCm' field.
* @param value the value to set.
*/
public void setSizeCm(Float value) {
this.sizeCm = value;
}
/** Creates a new Event RecordBuilder */
public static Event.Builder newBuilder() {
return new Event.Builder();
}
/** Creates a new Event RecordBuilder by copying an existing Builder */
public static Event.Builder newBuilder(Event.Builder other) {
return new Event.Builder(other);
}
/** Creates a new Event RecordBuilder by copying an existing Event instance */
public static Event.Builder newBuilder(Event other) {
return new Event.Builder(other);
}
/**
* RecordBuilder for Event instances.
*/
public static class Builder extends org.apache.avro.specific.SpecificRecordBuilderBase<Event>
implements org.apache.avro.data.RecordBuilder<Event> {
private long timestampMS;
private CharSequence name;
private int ageYrs;
private float sizeCm;
/** Creates a new Builder */
private Builder() {
super(Event.SCHEMA$);
}
/** Creates a Builder by copying an existing Builder */
private Builder(Event.Builder other) {
super(other);
if (isValidValue(fields()[0], other.timestampMS)) {
this.timestampMS = data().deepCopy(fields()[0].schema(), other.timestampMS);
fieldSetFlags()[0] = true;
}
if (isValidValue(fields()[1], other.name)) {
this.name = data().deepCopy(fields()[1].schema(), other.name);
fieldSetFlags()[1] = true;
}
if (isValidValue(fields()[2], other.ageYrs)) {
this.ageYrs = data().deepCopy(fields()[2].schema(), other.ageYrs);
fieldSetFlags()[2] = true;
}
if (isValidValue(fields()[3], other.sizeCm)) {
this.sizeCm = data().deepCopy(fields()[3].schema(), other.sizeCm);
fieldSetFlags()[3] = true;
}
}
/** Creates a Builder by copying an existing Event instance */
private Builder(Event other) {
super(Event.SCHEMA$);
if (isValidValue(fields()[0], other.timestampMS)) {
this.timestampMS = data().deepCopy(fields()[0].schema(), other.timestampMS);
fieldSetFlags()[0] = true;
}
if (isValidValue(fields()[1], other.name)) {
this.name = data().deepCopy(fields()[1].schema(), other.name);
fieldSetFlags()[1] = true;
}
if (isValidValue(fields()[2], other.ageYrs)) {
this.ageYrs = data().deepCopy(fields()[2].schema(), other.ageYrs);
fieldSetFlags()[2] = true;
}
if (isValidValue(fields()[3], other.sizeCm)) {
this.sizeCm = data().deepCopy(fields()[3].schema(), other.sizeCm);
fieldSetFlags()[3] = true;
}
}
/** Gets the value of the 'timestampMS' field */
public Long getTimestampMS() {
return timestampMS;
}
/** Sets the value of the 'timestampMS' field */
public Event.Builder setTimestampMS(long value) {
validate(fields()[0], value);
this.timestampMS = value;
fieldSetFlags()[0] = true;
return this;
}
/** Checks whether the 'timestampMS' field has been set */
public boolean hasTimestampMS() {
return fieldSetFlags()[0];
}
/** Clears the value of the 'timestampMS' field */
public Event.Builder clearTimestampMS() {
fieldSetFlags()[0] = false;
return this;
}
/** Gets the value of the 'name' field */
public CharSequence getName() {
return name;
}
/** Sets the value of the 'name' field */
public Event.Builder setName(CharSequence value) {
validate(fields()[1], value);
this.name = value;
fieldSetFlags()[1] = true;
return this;
}
/** Checks whether the 'name' field has been set */
public boolean hasName() {
return fieldSetFlags()[1];
}
/** Clears the value of the 'name' field */
public Event.Builder clearName() {
name = null;
fieldSetFlags()[1] = false;
return this;
}
/** Gets the value of the 'ageYrs' field */
public Integer getAgeYrs() {
return ageYrs;
}
/** Sets the value of the 'ageYrs' field */
public Event.Builder setAgeYrs(int value) {
validate(fields()[2], value);
this.ageYrs = value;
fieldSetFlags()[2] = true;
return this;
}
/** Checks whether the 'ageYrs' field has been set */
public boolean hasAgeYrs() {
return fieldSetFlags()[2];
}
/** Clears the value of the 'ageYrs' field */
public Event.Builder clearAgeYrs() {
fieldSetFlags()[2] = false;
return this;
}
/** Gets the value of the 'sizeCm' field */
public Float getSizeCm() {
return sizeCm;
}
/** Sets the value of the 'sizeCm' field */
public Event.Builder setSizeCm(float value) {
validate(fields()[3], value);
this.sizeCm = value;
fieldSetFlags()[3] = true;
return this;
}
/** Checks whether the 'sizeCm' field has been set */
public boolean hasSizeCm() {
return fieldSetFlags()[3];
}
/** Clears the value of the 'sizeCm' field */
public Event.Builder clearSizeCm() {
fieldSetFlags()[3] = false;
return this;
}
@Override
public Event build() {
try {
Event record = new Event();
record.timestampMS = fieldSetFlags()[0] ? this.timestampMS : (Long) defaultValue(fields()[0]);
record.name = fieldSetFlags()[1] ? this.name : (CharSequence) defaultValue(fields()[1]);
record.ageYrs = fieldSetFlags()[2] ? this.ageYrs : (Integer) defaultValue(fields()[2]);
record.sizeCm = fieldSetFlags()[3] ? this.sizeCm : (Float) defaultValue(fields()[3]);
return record;
} catch (Exception e) {
throw new org.apache.avro.AvroRuntimeException(e);
}
}
}
}
只是为了完整性，您能否给出Event定义。我想尝试优化您的多线程代码... –
确定我已经添加了它 –