net.DialTimeout导致 线程 数暴涨

环境：go 1.15.6 mac 11.1 下面代码使用net.DialTimeout扫描端口是否开放，超时设置为1s，目标端口99%的都会触发超时 运行后大概率线程数超过8192，然后开始报错 尝试过： 1、去掉ants协程池管理库，直接起go程，依然存在问题 2、将协程并发数降低到1w，线程数依然暴涨，但是超过8192几率小一些 3、将net.DialTimeout换成net.Dial，线程数降到一百多，但是速度慢太多了，几分钟后dial才会自己返回err 在网上找到一片类似情况的文章：[一个 Go 程序系统线程暴涨的问题](https://zhuanlan.zhihu.com/p/22474724) 也是由timeout引起，现在想知道怎么到达有timeout的效果又不会让线程暴涨？ 还有一个问题，同时运行的go程过多（一万），tcp连接正常开放的端口也会扫不出来，可能不是个例，在网上找的一个go做的扫描工具也会存在目标数过多，扫不出来的情况  ```go func connectPort(addr string, timeout int) { conn, err := net.DialTimeout("tcp", addr, time.Duration(timeout)*time.Millisecond) if err != nil { return } defer conn.Close() println(addr) } ``` ```go main: ips := cidr.Expand(conf.ip) var wg sync.WaitGroup task := func(addr interface{}) { defer wg.Done() connectPort(addr.(string), conf.timeout) } // 已配置过maxfiles 102400 102400 p, _ := ants.NewPoolWithFunc(65536, task) defer p.Release() for _, ip := range ips { wg.Add(1) _ = p.Invoke(ip + ":" + conf.port) } wg.Wait() println(len(ips)) ``` ``` 报错： oroutine 3879 [runnable]: syscall.syscall(0x109e700, 0xdc0, 0x0, 0x0, 0x0, 0x0, 0x0) /usr/local/Cellar/go/1.15.6/libexec/src/runtime/sys_darwin.go:63 +0x2e syscall.Close(0xdc0, 0xc0002931c0, 0xc001c15840) /usr/local/Cellar/go/1.15.6/libexec/src/syscall/zsyscall_darwin_amd64.go:519 +0x4c internal/poll.(*FD).destroy(0xc0017d6180, 0x3215001, 0x0) /usr/local/Cellar/go/1.15.6/libexec/src/internal/poll/fd_unix.go:77 +0x43 internal/poll.(*FD).decref(0xc0017d6180, 0x1, 0x0) /usr/local/Cellar/go/1.15.6/libexec/src/internal/poll/fd_mutex.go:213 +0x45 internal/poll.(*FD).Close(0xc0017d6180, 0xc0017d6180, 0x0) /usr/local/Cellar/go/1.15.6/libexec/src/internal/poll/fd_unix.go:99 +0x4f net.(*netFD).Close(0xc0017d6180, 0x1167f20, 0xc0017d4d20) /usr/local/Cellar/go/1.15.6/libexec/src/net/fd_posix.go:37 +0x4f net.socket(0x1167f20, 0xc0017d4d20, 0x113d1f3, 0x3, 0x2, 0x1, 0x0, 0x0, 0x1168400, 0x0, ...) /usr/local/Cellar/go/1.15.6/libexec/src/net/sock_posix.go:71 +0x1f2 net.internetSocket(0x1167f20, 0xc0017d4d20, 0x113d1f3, 0x3, 0x1168400, 0x0, 0x1168400, 0xc0017aee70, 0x1, 0x0, ...) /usr/local/Cellar/go/1.15.6/libexec/src/net/ipsock_posix.go:141 +0x145 net.(*sysDialer).doDialTCP(0xc0017d6100, 0x1167f20, 0xc0017d4d20, 0x0, 0xc0017aee70, 0x111a660, 0x124c9a0, 0x0) /usr/local/Cellar/go/1.15.6/libexec/src/net/tcpsock_posix.go:65 +0xc5 net.(*sysDialer).dialTCP(0xc0017d6100, 0x1167f20, 0xc0017d4d20, 0x0, 0xc0017aee70, 0x106a9a0, 0xc001c15b50, 0x655abf5a) /usr/local/Cellar/go/1.15.6/libexec/src/net/tcpsock_posix.go:61 +0xd7 net.(*sysDialer).dialSingle(0xc0017d6100, 0x1167f20, 0xc0017d4d20, 0x1167260, 0xc0017aee70, 0x0, 0x0, 0x0, 0x0) /usr/local/Cellar/go/1.15.6/libexec/src/net/dial.go:580 +0x5e5 net.(*sysDialer).dialSerial(0xc0017d6100, 0x1167f20, 0xc0017d4d20, 0xc0017bc950, 0x1, 0x1, 0x0, 0x0, 0x0, 0x0) /usr/local/Cellar/go/1.15.6/libexec/src/net/dial.go:548 +0x152 net.(*Dialer).DialContext(0xc001c15e60, 0x1167ee0, 0xc000016100, 0x113d1f3, 0x3, 0xc000538ec0, 0x11, 0x0, 0x0, 0x0, ...) /usr/local/Cellar/go/1.15.6/libexec/src/net/dial.go:425 +0x6e5 net.(*Dialer).Dial(...) /usr/local/Cellar/go/1.15.6/libexec/src/net/dial.go:348 net.DialTimeout(0x113d1f3, 0x3, 0xc000538ec0, 0x11, 0x3b9aca00, 0x0, 0xc00152e310, 0xc0015195b8, 0x0) /usr/local/Cellar/go/1.15.6/libexec/src/net/dial.go:334 +0xba main.connectPort(0xc000538ec0, 0x11, 0x3e8) /Library/project/gostart/1.go:27 +0x6f main.main.func1(0x1113940, 0xc00152e300) /Library/project/gostart/1.go:77 +0x7c github.com/panjf2000/ants/v2.(*goWorkerWithFunc).run.func1(0xc001542030) /Library/project/gostart/vendor/github.com/panjf2000/ants/v2/worker_func.go:68 +0xb0 created by github.com/panjf2000/ants/v2.(*goWorkerWithFunc).run /Library/project/gostart/vendor/github.com/panjf2000/ants/v2/worker_func.go:48 +0x4c ```