Dubbo性能調優參數及原理

時間 2019-11-13

標籤 dubbo 性能參數原理欄目 Dubbo 简体版

原文原文鏈接

github新增倉庫 "dubbo-read"（點此查看），集合全部《Dubbo原理和源碼解析》系列文章，後續將繼續補充該系列，同時將針對Dubbo所作的功能擴展也進行分享。不按期更新，歡迎Follow。

本文是針對 Dubbo 協議調用的調優指導，詳細說明經常使用調優參數的做用域及源碼。java

Dubbo調用模型git

經常使用性能調優參數github

參數名	做用範圍	默認值	說明	備註
threads	provider	200	業務處理線程池大小
iothreads	provider	CPU+1	io線程池大小
queues	provider	0	線程池隊列大小，當線程池滿時，排隊等待執行的隊列大小，bootstrap 建議不要設置，當線程程池時應當即失敗，併發重試其它服務提供機器，而不是排隊，除非有特殊需求ide
connections	consumer	0	對每一個提供者的最大鏈接數，性能 rmi、http、hessian等短鏈接協議表示限制鏈接數，this Dubbo等長鏈接協表示創建的長鏈接個數url	Dubbo協議默認共享一個長鏈接
actives	consumer	0	每服務消費者每服務每方法最大併發調用數	0表示不限制
acceptes	provider	0	服務提供方最大可接受鏈接數	0表示不限制
executes	provider	0	服務提供者每服務每方法最大可並行執行請求數	0表示不限制

源碼及原理分析spa

>> 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 參數配置的是業務處理線程池的最大（或核心）線程數。

>> iothreads

NettyServer.java

@Override
protected 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

分別在 FixedThreadPool.java、LimitedThreadPool.java 和 CachedThreadPool.java 中使用，代碼詳情見 3.2章節。由代碼可見，默認值爲 0，表示使用同步阻塞隊列；若是 queues 設置爲小於 0 的值，則使用容量爲 Integer.MAX_VALUE 的阻塞鏈表隊列；若是爲其餘值，則使用指定大小的阻塞鏈表隊列。

>> connections

DubboProtocol.java

private ExchangeClient[] getClients(URL url){
    //是否共享鏈接
    boolean service_share_connect = false;
    int connections = url.getParameter(Constants.CONNECTIONS_KEY, 0);
    //若是connections不配置，則共享鏈接，不然每服務每鏈接
    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

@Override
protected 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);
    }
}

以上可見，默認值爲0，表示針對每一個 Provider，全部客戶端共享一個長鏈接；不然，創建指定數量的長鏈接。在調用時，若是有多個長鏈接，則使用輪詢方式得到一個長鏈接。

>> 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 調用時，統計服務和方法維度的調用狀況，若是併發數超過設置的最大值，則阻塞當前線程，直到前面有請求處理完成。

>> accepts

AbstractServer.java

@Override
public 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);
}

當鏈接數大於最大值時，關閉當前鏈接。

>> 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);
    }
}