moby/pkg/sysinfo/numcpu_windows.go
Yong Tang 3707a76921 Fix wrong CPU count after CPU hot-plugging on Windows
This fix tries to fix wrong CPU count after CPU hot-plugging.
On windows, GetProcessAffinityMask has been used to probe the
number of CPUs in real time.

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>
2016-06-25 22:20:29 -07:00

36 lines
844 B
Go

// +build windows
package sysinfo
import (
"runtime"
"syscall"
"unsafe"
)
var (
kernel32 = syscall.NewLazyDLL("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()
}