From 48e0e1106353f3e9ac1aeb739399b674657227cf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan-Otto=20Kr=C3=B6pke?= <github@jkroepke.de>
Date: Tue, 1 Oct 2024 10:53:13 +0200
Subject: [PATCH] cpu: add workaround for counter resets related to `%
 Processor Utility` metric (#1637)

---
 pkg/collector/cpu/cpu.go | 63 ++++++++++++++++++++++++++++++++++++++--
 1 file changed, 61 insertions(+), 2 deletions(-)

diff --git a/pkg/collector/cpu/cpu.go b/pkg/collector/cpu/cpu.go
index a3482ff3..6805cc0d 100644
--- a/pkg/collector/cpu/cpu.go
+++ b/pkg/collector/cpu/cpu.go
@@ -27,6 +27,9 @@ type Collector struct {
 
 	perfDataCollector *perfdata.Collector
 
+	processorRTCValues   map[string]cpuCounter
+	processorMPerfValues map[string]cpuCounter
+
 	logicalProcessors          *prometheus.Desc
 	cStateSecondsTotal         *prometheus.Desc
 	timeTotal                  *prometheus.Desc
@@ -43,6 +46,11 @@ type Collector struct {
 	processorPrivilegedUtility *prometheus.Desc
 }
 
+type cpuCounter struct {
+	lastValue  uint32
+	totalValue float64
+}
+
 func New(config *Config) *Collector {
 	if config == nil {
 		config = &ConfigDefaults
@@ -221,6 +229,9 @@ func (c *Collector) Build(_ *slog.Logger, _ *wmi.Client) error {
 		nil,
 	)
 
+	c.processorRTCValues = map[string]cpuCounter{}
+	c.processorMPerfValues = map[string]cpuCounter{}
+
 	return nil
 }
 
@@ -251,6 +262,30 @@ 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),
+			}
+		} else {
+			c.processorRTCValues[core] = cpuCounter{
+				uint32(cpu.ProcessorRTC),
+				0,
+			}
+		}
+
+		if val, ok := c.processorMPerfValues[core]; ok {
+			c.processorMPerfValues[core] = cpuCounter{
+				uint32(cpu.ProcessorMPerf),
+				val.totalValue + float64(uint32(cpu.ProcessorMPerf)-val.lastValue),
+			}
+		} else {
+			c.processorMPerfValues[core] = cpuCounter{
+				uint32(cpu.ProcessorMPerf),
+				0,
+			}
+		}
+
 		coreCount++
 
 		ch <- prometheus.MustNewConstMetric(
@@ -350,13 +385,13 @@ func (c *Collector) collectFull(ctx *types.ScrapeContext, logger *slog.Logger, c
 		ch <- prometheus.MustNewConstMetric(
 			c.processorMPerf,
 			prometheus.CounterValue,
-			cpu.ProcessorMPerf,
+			c.processorMPerfValues[core].totalValue,
 			core,
 		)
 		ch <- prometheus.MustNewConstMetric(
 			c.processorRTC,
 			prometheus.CounterValue,
-			cpu.ProcessorRTC,
+			c.processorRTCValues[core].totalValue,
 			core,
 		)
 		ch <- prometheus.MustNewConstMetric(
@@ -393,6 +428,30 @@ 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),
+			}
+		} else {
+			c.processorRTCValues[core] = cpuCounter{
+				uint32(coreData[privilegedUtilitySeconds].SecondValue),
+				0,
+			}
+		}
+
+		if val, ok := c.processorMPerfValues[core]; ok {
+			c.processorMPerfValues[core] = cpuCounter{
+				uint32(coreData[processorPerformance].SecondValue),
+				val.totalValue + float64(uint32(coreData[processorPerformance].SecondValue)-val.lastValue),
+			}
+		} else {
+			c.processorMPerfValues[core] = cpuCounter{
+				uint32(coreData[processorPerformance].SecondValue),
+				0,
+			}
+		}
+
 		ch <- prometheus.MustNewConstMetric(
 			c.cStateSecondsTotal,
 			prometheus.CounterValue,