Dubbo调用模型
常用性能调优参数
源码及原理分析
>> threads
FixedThreadPool.java
public Executor getExecutor(URL url) {
String name = url.getParameter(Constants.THREAD_NAME_KEY, Constants.DEFAULT_THREAD_NAME); int threads = url.getParameter(Constants.THREADS_KEY, Constants.DEFAULT_THREADS); int queues = url.getParameter(Constants.QUEUES_KEY, Constants.DEFAULT_QUEUES); return new ThreadPoolExecutor(threads, threads, 0, TimeUnit.MILLISECONDS,
queues == 0 ? new SynchronousQueue<Runnable>() :
(queues < 0 ? new LinkedBlockingQueue<Runnable>() :
new LinkedBlockingQueue<Runnable>(queues)), new NamedThreadFactory(name, true), new AbortPolicyWithReport(name, url));
}
LimitedThreadPool.java
public Executor getExecutor(URL url) {
String name = url.getParameter(Constants.THREAD_NAME_KEY, Constants.DEFAULT_THREAD_NAME); int cores = url.getParameter(Constants.CORE_THREADS_KEY, Constants.DEFAULT_CORE_THREADS); int threads = url.getParameter(Constants.THREADS_KEY, Constants.DEFAULT_THREADS); int queues = url.getParameter(Constants.QUEUES_KEY, Constants.DEFAULT_QUEUES); return new ThreadPoolExecutor(cores, threads, Long.MAX_VALUE, TimeUnit.MILLISECONDS,
queues == 0 ? new SynchronousQueue<Runnable>() :
(queues < 0 ? new LinkedBlockingQueue<Runnable>() :
new LinkedBlockingQueue<Runnable>(queues)), new NamedThreadFactory(name, true), new AbortPolicyWithReport(name, url));
}
其中，Constants.DEFAULT_QUEUES = 200。threads 参数配置的是业务处理线程池的最大（或核心）线程数。
>> iothreads
NettyServer.java
@Overrideprotected void doOpen() throws Throwable {
NettyHelper.setNettyLoggerFactory();
ExecutorService boss = Executors.newCachedThreadPool(new NamedThreadFactory("NettyServerBoss", true));
ExecutorService worker = Executors.newCachedThreadPool(new NamedThreadFactory("NettyServerWorker", true));
ChannelFactory channelFactory = new NioServerSocketChannelFactory(boss, worker, getUrl().getPositiveParameter(Constants.IO_THREADS_KEY, Constants.DEFAULT_IO_THREADS));
bootstrap = new ServerBootstrap(channelFactory);
final NettyHandler nettyHandler = new NettyHandler(getUrl(), this);
channels = nettyHandler.getChannels();
bootstrap.setPipelineFactory(new ChannelPipelineFactory() { public ChannelPipeline getPipeline() {
NettyCodecAdapter adapter = new NettyCodecAdapter(getCodec() ,getUrl(), NettyServer.this);
ChannelPipeline pipeline = Channels.pipeline();
pipeline.addLast("decoder", adapter.getDecoder());
pipeline.addLast("encoder", adapter.getEncoder());
pipeline.addLast("handler", nettyHandler); return pipeline;
}
}); // bind
channel = bootstrap.bind(getBindAddress());
}
>> queues
分别在FixedThreadPool.java、LimitedThreadPool.java 和 CachedThreadPool.java 中使用，代码详情见 3.2章节。由代码可见，默认值为 0，表示使用同步阻塞队列；如果 queues 设置为小于 0 的值，则使用容量为 Integer.MAX_VALUE 的阻塞链表队列；如果为其他值，则使用指定大小的阻塞链表队列。
>> connections
DubboProtocol.java
private ExchangeClient[] getClients(URL url){ //是否共享连接
boolean service_share_connect = false; int connections = url.getParameter(Constants.CONNECTIONS_KEY, 0); //如果connections不配置，则共享连接，否则每服务每连接
if (connections == 0){
service_share_connect = true;
connections = 1;
}
ExchangeClient[] clients = new ExchangeClient[connections]; for (int i = 0; i < clients.length; i++) { if (service_share_connect){
clients[i] = getSharedClient(url);
} else {
clients[i] = initClient(url);
}
} return clients;
}
DubboInvoker.java
@Overrideprotected Result doInvoke(final Invocation invocation) throws Throwable {
RpcInvocation inv = (RpcInvocation) invocation; final String methodName = RpcUtils.getMethodName(invocation);
inv.setAttachment(Constants.PATH_KEY, getUrl().getPath());
inv.setAttachment(Constants.VERSION_KEY, version);
ExchangeClient currentClient; if (clients.length == 1) {
currentClient = clients[0];
} else {
currentClient = clients[index.getAndIncrement() % clients.length];
} try { boolean isAsync = RpcUtils.isAsync(getUrl(), invocation); boolean isOneway = RpcUtils.isOneway(getUrl(), invocation); int timeout = getUrl().getMethodParameter(methodName, Constants.TIMEOUT_KEY,Constants.DEFAULT_TIMEOUT); if (isOneway) { boolean isSent = getUrl().getMethodParameter(methodName, Constants.SENT_KEY, false);
currentClient.send(inv, isSent);
RpcContext.getContext().setFuture(null); return new RpcResult();
} else if (isAsync) {
ResponseFuture future = currentClient.request(inv, timeout) ;
RpcContext.getContext().setFuture(new FutureAdapter<Object>(future)); return new RpcResult();
} else {
RpcContext.getContext().setFuture(null); return (Result) currentClient.request(inv, timeout).get();
}
} catch (TimeoutException e) { throw new RpcException(RpcException.TIMEOUT_EXCEPTION, "Invoke remote method timeout. method: " + invocation.getMethodName() + ", provider: " + getUrl() + ", cause: " + e.getMessage(), e);
} catch (RemotingException e) { throw new RpcException(RpcException.NETWORK_EXCEPTION, "Failed to invoke remote method: " + invocation.getMethodName() + ", provider: " + getUrl() + ", cause: " + e.getMessage(), e);
}
}
以上可见，默认值为0，表示针对每个 Provider，所有客户端共享一个长连接；否则，建立指定数量的长连接。在调用时，如果有多个长连接，则使用轮询方式获得一个长连接。
>> actives
ActiveLimitFilter.java
public Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcException {
URL url = invoker.getUrl();
String methodName = invocation.getMethodName(); int max = invoker.getUrl().getMethodParameter(methodName, Constants.ACTIVES_KEY, 0);
RpcStatus count = RpcStatus.getStatus(invoker.getUrl(), invocation.getMethodName()); if (max > 0) { long timeout = invoker.getUrl().getMethodParameter(invocation.getMethodName(), Constants.TIMEOUT_KEY, 0); long start = System.currentTimeMillis(); long remain = timeout; int active = count.getActive(); if (active >= max) { synchronized (count) { while ((active = count.getActive()) >= max) { try {
count.wait(remain);
} catch (InterruptedException e) {
} long elapsed = System.currentTimeMillis() - start;
remain = timeout - elapsed; if (remain <= 0) { throw new RpcException("Waiting concurrent invoke timeout in client-side for service: "
+ invoker.getInterface().getName() + ", method: "
+ invocation.getMethodName() + ", elapsed: " + elapsed + ", timeout: " + timeout + ". concurrent invokes: " + active + ". max concurrent invoke limit: " + max);
}
}
}
}
} try { long begin = System.currentTimeMillis();
RpcStatus.beginCount(url, methodName); try {
Result result = invoker.invoke(invocation);
RpcStatus.endCount(url, methodName, System.currentTimeMillis() - begin, true); return result;
} catch (RuntimeException t) {
RpcStatus.endCount(url, methodName, System.currentTimeMillis() - begin, false); throw t;
}
} finally { if(max>0){ synchronized (count) {
count.notify();
}
}
}
}
Consumer 调用时，统计服务和方法维度的调用情况，如果并发数超过设置的最大值，则阻塞当前线程，直到前面有请求处理完成。
>> accepts
AbstractServer.java
@Overridepublic void connected(Channel ch) throws RemotingException {
Collection<Channel> channels = getChannels(); if (accepts > 0 && channels.size() > accepts) {
logger.error("Close channel " + ch + ", cause: The server " + ch.getLocalAddress() + " connections greater than max config " + accepts);
ch.close(); return;
} super.connected(ch);
}
当连接数大于最大值时，关闭当前连接。
>> executes
ExecuteLimitFilter.jvava
public Result invokeOrg(Invoker<?> invoker, Invocation invocation) throws RpcException {
URL url = invoker.getUrl();
String methodName = invocation.getMethodName(); int max = url.getMethodParameter(methodName, Constants.EXECUTES_KEY, 0); if (max > 0) {
RpcStatus count = RpcStatus.getStatus(url, invocation.getMethodName()); if (count.getActive() >= max) { throw new RpcException("Failed to invoke method " + invocation.getMethodName() + " in provider " + url + ", cause: The service using threads greater than <dubbo:service executes=\"" + max + "\" /> limited.");
}
} long begin = System.currentTimeMillis(); boolean isException = false;
RpcStatus.beginCount(url, methodName); try {
Result result = invoker.invoke(invocation); return result;
} catch (Throwable t) {
isException = true; if(t instanceof RuntimeException) { throw (RuntimeException) t;
} else { throw new RpcException("unexpected exception when ExecuteLimitFilter", t);
}
} finally {
RpcStatus.endCount(url, methodName, System.currentTimeMillis() - begin, isException);
}
}
作者：java菜
链接：https://www.jianshu.com/p/2e66d328c9f1
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