settings.go

package optimal

import (
	"github.com/daanv2/go-optimal/pkg/cpu"
	env "github.com/daanv2/go-optimal/pkg/environment"
)

func init() {
	tempTarget, found := env.Int64.LookupIf("CPU_CACHE_OPTIMAL_SIZE")
	if !found {
		tempTarget = OptimalBytesForCache(cpu.GetDefaultCacheTarget())
	}

	targetSize = tempTarget
}

// OptimalBytesForCache returns the optimal amount of bytes that can be used in a cache
func OptimalBytesForCache(cache cpu.CacheKind) int64 {
	switch cache {
	default:
		fallthrough
	case cpu.CacheL3:
		// 95% of the L3
		size := cpu.GetCacheSize(cpu.CacheL3)

		return percentage(size, 95)

	case cpu.CacheL2:
		// 90% of the L2
		size := cpu.GetCacheSize(cpu.CacheL2)

		return percentage(size, 90)

	case cpu.CacheL1:
		// 60% of the L1 cache
		size := cpu.GetCacheSize(cpu.CacheL1)

		return percentage(size, 60)
	}
}

func percentage(value, percentage int64) int64 {
	return (value * percentage) / 100
}

// The amount of bytes data can maximally be
var targetSize int64

// GetTargetSize The target size in bytes of what can be used in a cache
func GetTargetSize() int64 {
	return targetSize
}

// GetTargetSizeFor returns the target size in bytes of what can be used in a cache
func GetTargetSizeFor(kind cpu.CacheKind) int64 {
	return OptimalBytesForCache(kind)
}

// SetTargetSize sets the target size in bytes of what can be used in a cache
func SetTargetSize(size int64) {
	targetSize = size
}