kubelet: fix the bug that the number of cpu cannot be obtained normal…

…ly under Windows

pkg/kubelet/winstats/perfcounter_nodestats.go

@@ -26,6 +26,7 @@ import (
 	"runtime"
 	"strings"
 	"sync"
+	"syscall"
 	"time"
 	"unsafe"
 
@@ -50,10 +51,13 @@ type MemoryStatusEx struct {
 }
 
 var (
-	modkernel32              = windows.NewLazySystemDLL("kernel32.dll")
-	procGlobalMemoryStatusEx = modkernel32.NewProc("GlobalMemoryStatusEx")
+	modkernel32                 = windows.NewLazySystemDLL("kernel32.dll")
+	procGlobalMemoryStatusEx    = modkernel32.NewProc("GlobalMemoryStatusEx")
+	procGetActiveProcessorCount = modkernel32.NewProc("GetActiveProcessorCount")
 )
 
+const allProcessorGroups = 0xFFFF
+
 // NewPerfCounterClient creates a client using perf counters
 func NewPerfCounterClient() (Client, error) {
 	// Initialize the cache
@@ -140,13 +144,33 @@ func (p *perfCounterNodeStatsClient) getMachineInfo() (*cadvisorapi.MachineInfo,
 	}
 
 	return &cadvisorapi.MachineInfo{
-		NumCores:       runtime.NumCPU(),
+		NumCores:       processorCount(),
 		MemoryCapacity: p.nodeInfo.memoryPhysicalCapacityBytes,
 		MachineID:      hostname,
 		SystemUUID:     systemUUID,
 	}, nil
 }
 
+// runtime.NumCPU() will only return the information for a single Processor Group.
+// Since a single group can only hold 64 logical processors, this
+// means when there are more they will be divided into multiple groups.
+// For the above reason, procGetActiveProcessorCount is used to get the
+// cpu count for all processor groups of the windows node.
+// more notes for this issue:
+// same issue in moby: https://github.com/moby/moby/issues/38935#issuecomment-744638345
+// solution in hcsshim: https://github.com/microsoft/hcsshim/blob/master/internal/processorinfo/processor_count.go
+func processorCount() int {
+	if amount := getActiveProcessorCount(allProcessorGroups); amount != 0 {
+		return int(amount)
+	}
+	return runtime.NumCPU()
+}
+
+func getActiveProcessorCount(groupNumber uint16) int {
+	r0, _, _ := syscall.Syscall(procGetActiveProcessorCount.Addr(), 1, uintptr(groupNumber), 0, 0)
+	return int(r0)
+}
+
 func (p *perfCounterNodeStatsClient) getVersionInfo() (*cadvisorapi.VersionInfo, error) {
 	return &cadvisorapi.VersionInfo{
 		KernelVersion:      p.nodeInfo.kernelVersion,