add load to windows

internal/common/common_windows.go

@@ -4,6 +4,7 @@ package common
 
 import (
 	"context"
+	"fmt"
 	"path/filepath"
 	"strings"
 	"syscall"
@@ -69,13 +70,13 @@ var (
 	ProcNtWow64QueryInformationProcess64 = ModNt.NewProc("NtWow64QueryInformationProcess64")
 	ProcNtWow64ReadVirtualMemory64       = ModNt.NewProc("NtWow64ReadVirtualMemory64")
 
-	PdhOpenQuery                         = ModPdh.NewProc("PdhOpenQuery")
-	PdhAddCounter                        = ModPdh.NewProc("PdhAddCounterW")
-	PdhCollectQueryData                  = ModPdh.NewProc("PdhCollectQueryData")
-	PdhGetFormattedCounterValue          = ModPdh.NewProc("PdhGetFormattedCounterValue")
-	PdhCloseQuery                        = ModPdh.NewProc("PdhCloseQuery")
+	PdhOpenQuery                = ModPdh.NewProc("PdhOpenQuery")
+	PdhAddCounter               = ModPdh.NewProc("PdhAddCounterW")
+	PdhCollectQueryData         = ModPdh.NewProc("PdhCollectQueryData")
+	PdhGetFormattedCounterValue = ModPdh.NewProc("PdhGetFormattedCounterValue")
+	PdhCloseQuery               = ModPdh.NewProc("PdhCloseQuery")
 
-	procQueryDosDeviceW                  = Modkernel32.NewProc("QueryDosDeviceW")
+	procQueryDosDeviceW = Modkernel32.NewProc("QueryDosDeviceW")
 )
 
 type FILETIME struct {
@@ -93,7 +94,7 @@ func BytePtrToString(p *uint8) string {
 	return string(a[:i])
 }
 
-// CounterInfo
+// CounterInfo XXX
 // copied from https://github.com/mackerelio/mackerel-agent/
 type CounterInfo struct {
 	PostName    string
@@ -130,6 +131,57 @@ func CreateCounter(query windows.Handle, pname, cname string) (*CounterInfo, err
 	}, nil
 }
 
+// GetCounterValue get counter value from handle
+// adapted from https://github.com/mackerelio/mackerel-agent/
+func GetCounterValue(counter windows.Handle) (float64, error) {
+	var value PDH_FMT_COUNTERVALUE_DOUBLE
+	r, _, err := PdhGetFormattedCounterValue.Call(uintptr(counter), PDH_FMT_DOUBLE, uintptr(0), uintptr(unsafe.Pointer(&value)))
+	if r != 0 && r != PDH_INVALID_DATA {
+		return 0.0, err
+	}
+	return value.DoubleValue, nil
+}
+
+// ProcessorQueueLengthGenerator is struct of windows api
+// adapted from https://github.com/mackerelio/mackerel-agent/
+type ProcessorQueueLengthGenerator struct {
+	query   windows.Handle
+	counter *CounterInfo
+}
+
+// NewProcessorQueueLengthGenerator is set up windows api
+// adapted from https://github.com/mackerelio/mackerel-agent/
+func NewProcessorQueueLengthGenerator() (*ProcessorQueueLengthGenerator, error) {
+	g := &ProcessorQueueLengthGenerator{0, nil}
+
+	var err error
+	g.query, err = CreateQuery()
+	if err != nil {
+		return nil, err
+	}
+
+	counter, err := CreateCounter(g.query, "processor_queue_length", `\System\Processor Queue Length`)
+	if err != nil {
+		return nil, err
+	}
+	g.counter = counter
+	return g, nil
+}
+
+// Generate XXX
+// adapted from https://github.com/mackerelio/mackerel-agent/
+func (g *ProcessorQueueLengthGenerator) Generate() (float64, error) {
+	r, _, err := PdhCollectQueryData.Call(uintptr(g.query))
+	if r != 0 && err != nil {
+		if r == PDH_NO_DATA {
+			return 0.0, fmt.Errorf("%w: this metric has not data", err)
+		}
+		return 0.0, err
+	}
+
+	return GetCounterValue(g.counter.Counter)
+}
+
 // WMIQueryWithContext - wraps wmi.Query with a timed-out context to avoid hanging
 func WMIQueryWithContext(ctx context.Context, query string, dst interface{}, connectServerArgs ...interface{}) error {
 	if _, ok := ctx.Deadline(); !ok {

load/load_test.go

@@ -27,6 +27,23 @@ func TestLoad(t *testing.T) {
 	t.Log(v)
 }
 
+// Commented out to not to slow down CI
+// Do conduct heavy cpu load on he computer to observe change
+// func TestLoadWithInterval(t *testing.T) {
+// 	interval := 5
+// 	iteration := 110 / interval
+
+// 	for i := 0; i < iteration; i++ {
+// 		v, err := Avg()
+// 		skipIfNotImplementedErr(t, err)
+// 		if err != nil {
+// 			t.Errorf("error %v", err)
+// 		}
+// 		t.Log(v)
+// 		time.Sleep(time.Duration(interval) * time.Second)
+// 	}
+// }
+
 func TestLoadAvgStat_String(t *testing.T) {
 	v := AvgStat{
 		Load1:  10.1,

load/load_windows.go

@@ -4,18 +4,75 @@ package load
 
 import (
 	"context"
+	"sync"
+	"time"
 
 	"github.com/shirou/gopsutil/internal/common"
 )
 
+var (
+	loadErr              error
+	loadAvg1M            float64 = 0.0
+	loadAvg5M            float64 = 0.0
+	loadAvg15M           float64 = 0.0
+	loadAvgMutex         sync.RWMutex
+	loadAvgGoroutineOnce sync.Once
+)
+
+// loadAvgGoroutine updates avg data by fetching current load by interval
+// TODO register callback rather than this
+// see https://psutil.readthedocs.io/en/latest/#psutil.getloadavg
+// code https://github.com/giampaolo/psutil/blob/master/psutil/arch/windows/wmi.c
+func loadAvgGoroutine() {
+	const (
+		loadAvgFactor1F  = 0.9200444146293232478931553241
+		loadAvgFactor5F  = 0.9834714538216174894737477501
+		loadAvgFactor15F = 0.9944598480048967508795473394
+	)
+
+	var (
+		interval = 5 * time.Second
+	)
+
+	generator, err := common.NewProcessorQueueLengthGenerator()
+	if err != nil {
+		loadAvgMutex.Lock()
+		loadErr = err
+		loadAvgMutex.Unlock()
+		return
+	}
+	for {
+		time.Sleep(interval)
+		if generator == nil {
+			return
+		}
+		currentLoad, err := generator.Generate()
+		loadAvgMutex.Lock()
+		loadErr = err
+		if err == nil {
+			loadAvg1M = loadAvg1M*loadAvgFactor1F + currentLoad*(1.0-loadAvgFactor1F)
+			loadAvg5M = loadAvg5M*loadAvgFactor5F + currentLoad*(1.0-loadAvgFactor5F)
+			loadAvg15M = loadAvg15M*loadAvgFactor15F + currentLoad*(1.0-loadAvgFactor15F)
+		}
+		loadAvgMutex.Unlock()
+	}
+}
+
 func Avg() (*AvgStat, error) {
 	return AvgWithContext(context.Background())
 }
 
 func AvgWithContext(ctx context.Context) (*AvgStat, error) {
-	ret := AvgStat{}
+	loadAvgGoroutineOnce.Do(func() { go loadAvgGoroutine() })
+	loadAvgMutex.RLock()
+	defer loadAvgMutex.RUnlock()
+	ret := AvgStat{
+		Load1:  loadAvg1M,
+		Load5:  loadAvg5M,
+		Load15: loadAvg15M,
+	}
 
-	return &ret, common.ErrNotImplementedError
+	return &ret, loadErr
 }
 
 func Misc() (*MiscStat, error) {