next article (§12) for details. return lines in function declarations. deferred function calls and goroutine creations. The two will be introduced in the article after next (§13). Examples of Expressions Function Calls and Panic/Recover This article will introduce goroutines and deferred function calls. Goroutine and deferred function call are two unique features in Go. This article also explains panic and recover program, a computer, or a network. In Go 101, we only talk about program-scope concurrent computing. Goroutine is the Go way to create concurrent computations in Go programming. Goroutines are also often called

article (§12) for details. return lines in function declarations. deferred function calls and goroutine creations. The two will be introduced in the article after next (§13). Examples of Expressions Function Calls and Panic/Recover This article will introduce goroutines and deferred function calls. Goroutine and deferred function call are two unique features in Go. This article also explains panic and recover program, a computer, or a network. In Go 101, we only talk about program-scope concurrent computing. Goroutine is the Go way to create concurrent computations in Go programming. Goroutines are also often called

article (§12) for details. return lines in function declarations. deferred function calls and goroutine creations. The two will be introduced in the article after next (§13). Examples of Expressions Function Calls and Panic/Recover This article will introduce goroutines and deferred function calls. Goroutine and deferred function call are two unique features in Go. This article also explains panic and recover program, a computer, or a network. In Go 101, we only talk about program-scope concurrent computing. Goroutine is the Go way to create concurrent computations in Go programming. Goroutines are also often called

14.2.5 Asynchronous channels—making a channel with a buffer ........................387 14.2.6 Goroutine using a channel for outputting result(s) ...................................388 14.2.7 Semaphore init() function is also frequently used when (for example for a server application) a backend() goroutine is required from the start of the application, like in: func init() { // setup preparations possibilities. There is also a function time.Sleep(Duration d), which pauses the current process (goroutine in fact, see § 14.1) for a Duration d. 4.9. Pointers Unlike Java and .NET, Go gives the programmer

Zabbix 必须 首先拥有一个监控项来创建触发器。必须有触发器才能创建动作。因此，如果你想收到 服务器 X 上的 CPU 负载过高的警报，必须首先为 8 服务器 X 创建一个主机条目，然后创建一个用于监控其 CPU 的监控项，然后是一个触发器，如果 CPU 过高则触发动作，然后通过通过动 作操作向您发送电子邮件。这可能看起来像很多步骤，其实使用模板并不需要。而且，由于这种设计，可以自定义创建非常灵活的设置。 检查监控项值的单调增加或减少。 更改计数 添加了一个新的历史函数changecount() ，允许计算相邻值之间的更改次数。该函数支持三种不同的模式：计算所有变化，只减少，或 者只增加。例如，它可用于跟踪用户数量的变化或系统正常运行时间的减少。 实体计数 添加了新的函数 来简化由foreach 函数 返回的特定主机、监控项或值的计数。 聚合函数： • count - foreach 函数返回的数组中值的总数（返回一个整数）； 新的和更新的监控项 Zabbix agent/agent 2 中添加了几个新监控项： • agent.hostmetadata - 返回主机元数据 • kernel.openfiles - 返回打开文件描述符的数量 • net.tcp.socket.count[] - 返回匹配参数的 TCP 套接字数 • net.udp.socket.count[] - 返回匹配参数的 UDP 套接字数 • vfs.dir

will not terminate until all of these functions return with panic to the first level of that goroutine . panic can be produced by calling panic in the program, and some errors also cause panic like array access out of bounds errors. Recover is a built-in function to recover goroutine s from panic status. Calling recover in defer functions is useful because normal functions will not concurrency is a hot topic in today's world, and Go supports this feature at the language level. goroutine goroutines and concurrency are built into the core design of Go. They're similar to threads but

/usr/local/go/src/runtime/asm_amd64.s:496 +0x49 fp=0x7fffb29cd820 sp=0x7fffb29cd818 pc=0x462329 goroutine 1 [running]: runtime.systemstack_switch() /usr/local/go/src/runtime/asm_amd64.s:463 fp=0xc00011bc68 /usr/local/go/src/runtime/asm_amd64.s:1598 +0x1 fp=0xc00011bfe8 sp=0xc00011bfe0 pc=0x4644e1 goroutine 2 [force gc (idle)]: runtime.gopark(0x0?, 0x0?, 0x0?, 0x0?, 0x0?) /usr/local/go/src/runtime/proc sp=0xc00004efe0 pc=0x4644e1 created by runtime.init.6 /usr/local/go/src/runtime/proc.go:293 +0x25 goroutine 3 [GC sweep wait]: runtime.gopark(0x0?, 0x0?, 0x0?, 0x0?, 0x0?) /usr/local/go/src/runtime/proc

Agenda Part I - Latency in scheduler ● The client consists of a goroutine and a channel ○ The channel batch the request ○ A goroutine run read-send-recv loop Background Description ● When the machine Network IO is ready => goroutine wake up == 4.3ms ○ Sometime even 10ms+ latency here! ○ The time spend on runtime schedule is not negligible ● When CPU is overload, which goroutine should be given priority priority? Analysis ● The goroutine is special, it block all the callers ● The scheduler treat them equally Analysis ● Under heavy workload, goroutines get longer to be scheduled ● The runtime scheduling

cheaper: • Smaller, segmented stacks. • Many goroutines per operating system thread. Start a new goroutine with the go keyword: i := pivot(s) go sort(s[:i]) go sort(s[i:]) 3 Google Confidential Concurrency: Google Confidential MROffice Dialer • Why Go works – The concurrency model suited the problem. A goroutine to handle each call, interviewer, and interviewee, all communicating via channels. – The http and Confidential Go at Atlassian • Read a configuration file. • Launch one goroutine for each VM in the cluster. • Each goroutine – listens for announcements from its corresponding VM, and – issues instructions

around on channels and, in fact, never actively shared by separate threads of execution. Only one goroutine has access to the value at any given time. Data races cannot occur, by design. To encourage this the existing terms—threads, coroutines, processes, and so on—convey inaccurate connotations. A goroutine has a simple model: it is a function executing concurrently with other goroutines in the same address Prefix a function or method call with the go keyword to run the call in a new goroutine. When the call completes, the goroutine exits, silently. (The effect is similar to the Unix shell's & notation for running