cpu: implement int32 counter for PDH calls as well.

Signed-off-by: Jan-Otto Kröpke <[email protected]>

internal/collector/cpu/cpu.go

@@ -27,8 +27,8 @@ type Collector struct {
 
 	perfDataCollector perfdata.Collector
 
-	processorRTCValues   map[string]cpuCounter
-	processorMPerfValues map[string]cpuCounter
+	processorRTCValues   map[string]utils.Counter
+	processorMPerfValues map[string]utils.Counter
 
 	logicalProcessors          *prometheus.Desc
 	cStateSecondsTotal         *prometheus.Desc
@@ -46,11 +46,6 @@ type Collector struct {
 	processorPrivilegedUtility *prometheus.Desc
 }
 
-type cpuCounter struct {
-	lastValue  uint32
-	totalValue float64
-}
-
 func New(config *Config) *Collector {
 	if config == nil {
 		config = &ConfigDefaults
@@ -229,8 +224,8 @@ func (c *Collector) Build(_ *slog.Logger, _ *wmi.Client) error {
 		nil,
 	)
 
-	c.processorRTCValues = map[string]cpuCounter{}
-	c.processorMPerfValues = map[string]cpuCounter{}
+	c.processorRTCValues = map[string]utils.Counter{}
+	c.processorMPerfValues = map[string]utils.Counter{}
 
 	return nil
 }
@@ -262,30 +257,28 @@ func (c *Collector) collectFull(ctx *types.ScrapeContext, logger *slog.Logger, c
 
 		core := cpu.Name
 
-		if val, ok := c.processorRTCValues[core]; ok {
-			c.processorRTCValues[core] = cpuCounter{
-				uint32(cpu.ProcessorRTC),
-				val.totalValue + float64(uint32(cpu.ProcessorRTC)-val.lastValue),
-			}
+		var (
+			counterProcessorRTCValues   utils.Counter
+			counterProcessorMPerfValues utils.Counter
+			ok                          bool
+		)
+
+		if counterProcessorRTCValues, ok = c.processorRTCValues[core]; ok {
+			counterProcessorRTCValues.AddValue(uint32(cpu.ProcessorRTC))
 		} else {
-			c.processorRTCValues[core] = cpuCounter{
-				uint32(cpu.ProcessorRTC),
-				0,
-			}
+			counterProcessorRTCValues = utils.NewCounter(uint32(cpu.ProcessorRTC))
 		}
 
-		if val, ok := c.processorMPerfValues[core]; ok {
-			c.processorMPerfValues[core] = cpuCounter{
-				uint32(cpu.ProcessorMPerf),
-				val.totalValue + float64(uint32(cpu.ProcessorMPerf)-val.lastValue),
-			}
+		c.processorRTCValues[core] = counterProcessorRTCValues
+
+		if counterProcessorMPerfValues, ok = c.processorMPerfValues[core]; ok {
+			counterProcessorMPerfValues.AddValue(uint32(cpu.ProcessorMPerf))
 		} else {
-			c.processorMPerfValues[core] = cpuCounter{
-				uint32(cpu.ProcessorMPerf),
-				0,
-			}
+			counterProcessorMPerfValues = utils.NewCounter(uint32(cpu.ProcessorMPerf))
 		}
 
+		c.processorMPerfValues[core] = counterProcessorMPerfValues
+
 		coreCount++
 
 		ch <- prometheus.MustNewConstMetric(
@@ -385,13 +378,13 @@ func (c *Collector) collectFull(ctx *types.ScrapeContext, logger *slog.Logger, c
 		ch <- prometheus.MustNewConstMetric(
 			c.processorMPerf,
 			prometheus.CounterValue,
-			c.processorMPerfValues[core].totalValue,
+			counterProcessorMPerfValues.Value(),
 			core,
 		)
 		ch <- prometheus.MustNewConstMetric(
 			c.processorRTC,
 			prometheus.CounterValue,
-			c.processorRTCValues[core].totalValue,
+			counterProcessorRTCValues.Value(),
 			core,
 		)
 		ch <- prometheus.MustNewConstMetric(
@@ -428,30 +421,28 @@ func (c *Collector) collectPDH(ch chan<- prometheus.Metric) error {
 	for core, coreData := range data {
 		coreCount++
 
-		if val, ok := c.processorRTCValues[core]; ok {
-			c.processorRTCValues[core] = cpuCounter{
-				uint32(coreData[privilegedUtilitySeconds].SecondValue),
-				val.totalValue + float64(uint32(coreData[privilegedUtilitySeconds].SecondValue)-val.lastValue),
-			}
+		var (
+			counterProcessorRTCValues   utils.Counter
+			counterProcessorMPerfValues utils.Counter
+			ok                          bool
+		)
+
+		if counterProcessorRTCValues, ok = c.processorRTCValues[core]; ok {
+			counterProcessorRTCValues.AddValue(uint32(coreData[processorUtilityRate].SecondValue))
 		} else {
-			c.processorRTCValues[core] = cpuCounter{
-				uint32(coreData[privilegedUtilitySeconds].SecondValue),
-				0,
-			}
+			counterProcessorRTCValues = utils.NewCounter(uint32(coreData[privilegedUtilitySeconds].SecondValue))
 		}
 
-		if val, ok := c.processorMPerfValues[core]; ok {
-			c.processorMPerfValues[core] = cpuCounter{
-				uint32(coreData[processorPerformance].SecondValue),
-				val.totalValue + float64(uint32(coreData[processorPerformance].SecondValue)-val.lastValue),
-			}
+		c.processorRTCValues[core] = counterProcessorRTCValues
+
+		if counterProcessorMPerfValues, ok = c.processorMPerfValues[core]; ok {
+			counterProcessorMPerfValues.AddValue(uint32(coreData[processorPerformance].SecondValue))
 		} else {
-			c.processorMPerfValues[core] = cpuCounter{
-				uint32(coreData[processorPerformance].SecondValue),
-				0,
-			}
+			counterProcessorMPerfValues = utils.NewCounter(uint32(coreData[processorPerformance].SecondValue))
 		}
 
+		c.processorMPerfValues[core] = counterProcessorMPerfValues
+
 		ch <- prometheus.MustNewConstMetric(
 			c.cStateSecondsTotal,
 			prometheus.CounterValue,
@@ -549,13 +540,13 @@ func (c *Collector) collectPDH(ch chan<- prometheus.Metric) error {
 		ch <- prometheus.MustNewConstMetric(
 			c.processorMPerf,
 			prometheus.CounterValue,
-			coreData[processorPerformance].SecondValue,
+			counterProcessorMPerfValues.Value(),
 			core,
 		)
 		ch <- prometheus.MustNewConstMetric(
 			c.processorRTC,
 			prometheus.CounterValue,
-			coreData[processorUtilityRate].SecondValue,
+			counterProcessorRTCValues.Value(),
 			core,
 		)
 		ch <- prometheus.MustNewConstMetric(

internal/utils/counter.go

@@ -0,0 +1,23 @@
+package utils
+
+type Counter struct {
+	lastValue  uint32
+	totalValue float64
+}
+
+// NewCounter creates a new Counter that accepts uint32 values and returns float64 values.
+// It resolve the overflow issue of uint32 by using the difference between the last value and the current value.
+func NewCounter(lastValue uint32) Counter {
+	return Counter{
+		lastValue:  lastValue,
+		totalValue: 0,
+	}
+}
+
+func (c *Counter) AddValue(value uint32) {
+	c.totalValue += float64(value - c.lastValue)
+}
+
+func (c *Counter) Value() float64 {
+	return c.totalValue
+}

internal/utils/counter_test.go

@@ -0,0 +1,24 @@
+package utils_test
+
+import (
+	"math"
+	"testing"
+
+	"github.com/prometheus-community/windows_exporter/internal/utils"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCounter(t *testing.T) {
+	t.Parallel()
+
+	c := utils.NewCounter(0)
+	assert.Equal(t, 0.0, c.Value())
+
+	c.AddValue(1)
+
+	assert.Equal(t, 1.0, c.Value())
+
+	c.AddValue(math.MaxUint32)
+
+	assert.Equal(t, float64(math.MaxUint32)+1.0, c.Value())
+}