Function ConvertCPUSharesToCgroupV2Value

cgroup2/utils.go:160–176

ConvertCPUSharesToCgroupV2Value converts CPU shares, used by cgroup v1, to CPU weight, used by cgroup v2. Cgroup v1 CPU shares has a range of [2^1...2^18], i.e. [2...262144], and the default value is 1024. Cgroup v2 CPU weight has a range of [10^0...10^4], i.e. [1...10000], and the default value i

(cpuShares uint64)

// Taken from https://github.com/opencontainers/cgroups/blob/v0.0.5/utils.go#L417-L441
// (Apache License 2.0)
func ConvertCPUSharesToCgroupV2Value(cpuShares uint64) uint64 {
	// The value of 0 means "unset".
	if cpuShares == 0 {
		return 0
	}
	if cpuShares <= 2 {
		return 1
	}
	if cpuShares >= 262144 {
		return 10000
	}
	l := math.Log2(float64(cpuShares))
	// Quadratic function which fits min, max, and default.
	exponent := (l*l+125*l)/612.0 - 7.0/34.0

	return uint64(math.Ceil(math.Pow(10, exponent)))
}

// ToResources converts the oci LinuxResources struct into a
// v2 Resources type for use with this package.