index_cpu.go

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package sync

// CoreFn is a function that returns the ID of the
// CPU currently running this goroutine.
type CoreFn func() int

var numCores = 1

func init() {
	numCores = checkNumCores()
}

// NumCores returns the number of cores returned from
// OS-dependent checkNumCores(), if not available only returns 1
func NumCores() int {
	return numCores
}

// CPUCore returns the current CPU core.
func CPUCore() int {
	if numCores == 1 {
		// Likely not linux and nothing available in procinfo meaning that
		// even if RDTSCP is available we won't have setup correct number
		// of cores, etc for our queues since we probed using NumCores
		// and got 1 back.
		return 0
	}
	// We know the number of cores, try to call RDTSCP to get the core.
	return getCore()
}