spring cloud gateway中netty线程池小优化

package reactor.netty.resources;
import io.netty.channel.Channel;
import io.netty.channel.EventLoopGroup;
import java.time.Duration;
import java.util.Objects;
import reactor.core.Disposable;
import reactor.core.publisher.Mono;
@FunctionalInterface
public interface LoopResources extends Disposable {
	// 这里是worker线程数，未配置的话。从cpu核心数和4直接取一个
    int DEFAULT_IO_WORKER_COUNT = Integer.parseInt(System.getProperty("reactor.netty.ioWorkerCount", "" + Math.max(Runtime.getRuntime().availableProcessors(), 4)));
    // 这里是select线程数 默认是-1
    int DEFAULT_IO_SELECT_COUNT = Integer.parseInt(System.getProperty("reactor.netty.ioSelectCount", "-1"));
    ....
    // 创建一个默认的资源，把两个线程数的参数传递过去
	static LoopResources create(String prefix) {
		if (Objects.requireNonNull(prefix, "prefix").isEmpty()) {
			throw new IllegalArgumentException("Cannot use empty prefix");
		}
		return new DefaultLoopResources(prefix, DEFAULT_IO_SELECT_COUNT, DEFAULT_IO_WORKER_COUNT, true);
	}
    ....

DefaultLoopResources(String prefix, int selectCount, int workerCount, boolean daemon) {
		this.running = new AtomicBoolean(true);
		this.daemon = daemon;
		this.workerCount = workerCount;
		this.prefix = prefix;
		this.serverLoops = new AtomicReference<>();
		this.clientLoops = new AtomicReference<>();
		this.cacheNativeClientLoops = new AtomicReference<>();
		this.cacheNativeServerLoops = new AtomicReference<>();
		// 因为默认没有配置 所以selectCode必然是-1
		if (selectCount == -1) {
			this.selectCount = workerCount;
			// serverSelectLoops没有创建，而是直接使用的serverLoops
			this.serverSelectLoops = this.serverLoops;
			this.cacheNativeSelectLoops = this.cacheNativeServerLoops;
		}
		else {
			this.selectCount = selectCount;
			this.serverSelectLoops = new AtomicReference<>();
			this.cacheNativeSelectLoops = new AtomicReference<>();
		}
	}
	@SuppressWarnings("FutureReturnValueIgnored")
	EventLoopGroup cacheNioSelectLoops() {
		// 两个相等的话 使用 cacheNioServerLoops 返回工作组
		if (serverSelectLoops == serverLoops) {
			return cacheNioServerLoops();
		}
		EventLoopGroup eventLoopGroup = serverSelectLoops.get();
		if (null == eventLoopGroup) {
			EventLoopGroup newEventLoopGroup = new NioEventLoopGroup(selectCount,
					threadFactory(this, "select-nio"));
			if (!serverSelectLoops.compareAndSet(null, newEventLoopGroup)) {
				//"FutureReturnValueIgnored" this is deliberate
				newEventLoopGroup.shutdownGracefully(0, 0, TimeUnit.MILLISECONDS);
			}
			eventLoopGroup = cacheNioSelectLoops();
		}
		return eventLoopGroup;
	}
	// 这里相当于返回了工作组
	@SuppressWarnings("FutureReturnValueIgnored")
	EventLoopGroup cacheNioServerLoops() {
		EventLoopGroup eventLoopGroup = serverLoops.get();
		if (null == eventLoopGroup) {
			EventLoopGroup newEventLoopGroup = new NioEventLoopGroup(workerCount,
					threadFactory(this, "nio"));
			if (!serverLoops.compareAndSet(null, newEventLoopGroup)) {
				//"FutureReturnValueIgnored" this is deliberate
				newEventLoopGroup.shutdownGracefully(0, 0, TimeUnit.MILLISECONDS);
			}
			eventLoopGroup = cacheNioServerLoops();
		}
		return eventLoopGroup;
	}

System.setProperty("reactor.netty.ioSelectCount","1");
// 这里工作线程数为2-4倍都可以。看具体情况
      System.setProperty("reactor.netty.ioWorkerCount",String.valueOf(Math.max(Runtime.getRuntime().availableProcessors()*3, 4)));