1 files changed, 37 insertions, 0 deletions
diff --git a/pkg/sysinfo/numcpu_windows.go b/pkg/sysinfo/numcpu_windows.go
new file mode 100644
index 000000000..1d89dd550
--- /dev/null
+++ b/pkg/sysinfo/numcpu_windows.go
@@ -0,0 +1,37 @@
+// +build windows
+
+package sysinfo
+
+import (
+	"runtime"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+var (
+	kernel32               = windows.NewLazySystemDLL("kernel32.dll")
+	getCurrentProcess      = kernel32.NewProc("GetCurrentProcess")
+	getProcessAffinityMask = kernel32.NewProc("GetProcessAffinityMask")
+)
+
+func numCPU() int {
+	// Gets the affinity mask for a process
+	var mask, sysmask uintptr
+	currentProcess, _, _ := getCurrentProcess.Call()
+	ret, _, _ := getProcessAffinityMask.Call(currentProcess, uintptr(unsafe.Pointer(&mask)), uintptr(unsafe.Pointer(&sysmask)))
+	if ret == 0 {
+		return 0
+	}
+	// For every available thread a bit is set in the mask.
+	ncpu := int(popcnt(uint64(mask)))
+	return ncpu
+}
+
+// NumCPU returns the number of CPUs which are currently online
+func NumCPU() int {
+	if ncpu := numCPU(); ncpu > 0 {
+		return ncpu
+	}
+	return runtime.NumCPU()
+}