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

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

improvement Go in TiDB • More than 100k lines of Go code and 94 contributors. Goroutine • Starting a goroutine is easy and cheap. • Goroutines come with built-in primitives to communicate safely Parallel HashJoin Operator Goroutine Leak • Write to a chan with no reader. • Read from a chan with no writer. • How to resolve? • Block profile • Timeout • Context Goroutine Leak Test • A useful tool