proc

Documentation

Overview

Package proc provides more fine-grained control over the Go runtime.

It also creates a new abstration: the inheritable goroutine ID, or IGID, which is automatically copied from parent to children goroutines.

Programs should use the Supported() API function to determine whether the Go runtime extension is available.

Index

• func GetDefaultPanicOnFault() bool
• func GetExternalErrorFd() int
• func GetGID() int64
• func GetGoroutineStackSize() uintptr
• func GetIGID() int64
• func GetOSThreadID() uint64
• func GetPID() int32
• func PinGoroutine() int
• func SetDefaultPanicOnFault(enabled bool) bool
• func SetExternalErrorFd(fd int)
• func SetIGID(igid int64)
• func Supported() bool
• func UnpinGoroutine()

Functions

func GetDefaultPanicOnFault

func GetDefaultPanicOnFault() bool

GetDefaultPanicOnFault retrieves the default value of the "panic on fault" flag.

Returns false if the extension is not supported.

func GetExternalErrorFd

func GetExternalErrorFd() int

GetExternalErrorFd retrieves the file descriptor used to emit panic messages and other internal errors by the go runtime.

Returns -1 if the extension is not supported.

func GetGID

func GetGID() int64

GetGID retrieves the goroutine (G's) ID.

This works even when the extension is not supported, by relying on github.com/petermattis/goid.

func GetGoroutineStackSize

func GetGoroutineStackSize() uintptr

GetGoroutineStackSize retrieves an approximation of the current goroutine (G)'s stack size.

Returns 0 if the extension is not supported.

func GetIGID

func GetIGID() int64

GetIGID retrieves the inheritable goroutine ID (IGID). This is inherited from the goroutine's parent. Top-level goroutines are assigned their own ID as group ID.

Returns 0 if the extension is not supported.

func GetOSThreadID

func GetOSThreadID() uint64

GetOSThreadID retrieves the OS-level thread ID, which can be used to e.g. set scheduling policies or retrieve CPU usage statistics.

Note: because of preemption, there is no guarantee that the current goroutine remains on the same OS thread after a call to this function completes. See Pin/UnpinGoroutine.

Returns 0 if the extension is not supported.

func GetPID

func GetPID() int32

GetPID retrieves the P (virtual CPU) ID of the current goroutine. These are by design set between 0 and gomaxprocs - 1. This can be used to create data structures with CPU affinity.

Note: because of preemption, there is no guarantee that the goroutine remains on the same P after the call to GetPID() completes. See Pin/UnpinGoroutine().

Returns 0 if the extension is not supported.

func PinGoroutine

func PinGoroutine() int

PinGoroutine pins the current G to its P and disables preemption. The caller is responsible for calling Unpin. The GC is not running between Pin and Unpin. Returns the ID of the P that the G has been pinned to.

Returns -1 if the extension is not supported.

func SetDefaultPanicOnFault

func SetDefaultPanicOnFault(enabled bool) bool

SetDefaultPanicOnFault sets the default value of the "panic on fault" that is otherwise customizable with debug.SetPanicOnFault.

The default value is used for "top level" goroutines that are started during the init process / runtime. The flag is inherited to children goroutines. When not customized, the go runtime uses "false" as default.

Returns false if the extension is not supported.

func SetExternalErrorFd

func SetExternalErrorFd(fd int)

SetExternalErrorFd changes the file descriptor used to emit panic messages and other internal errors by the go runtime.

No-op if the extension is not supported.

func SetIGID

func SetIGID(igid int64)

SetIGID sets the current goroutine's inheritable goroutine ID. This value is inherited to children goroutines.

A possible good value to use is the value of GetGID(), to obtain a behavior similar to process group IDs on unix.

No-op if the extension is not supported.

func Supported

func Supported() bool

Supported returns true iff the Go ID extension is available in the Go runtime.

func UnpinGoroutine

func UnpinGoroutine()

UnpinGoroutine unpints the current G from its P. The caller is responsible for ensuring that PinGoroutine() has been called first. The behavior is undefined otherwise.

No-op if the extension is not supported.