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moby--moby/pkg/sysinfo/numcpu_windows.go
Darren Stahl 22c83c567f Swap usage of LazyDLL and LoadDLL to LazySystemDLL.
Signed-off-by: Darren Stahl <darst@microsoft.com>
2016-11-22 14:57:11 -08:00

37 lines
868 B
Go

// +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()
}