| package sysinfo // import "github.com/docker/docker/pkg/sysinfo" |
| |
| import ( |
| "unsafe" |
| |
| "golang.org/x/sys/windows" |
| ) |
| |
| var ( |
| kernel32 = windows.NewLazySystemDLL("kernel32.dll") |
| getCurrentProcess = kernel32.NewProc("GetCurrentProcess") |
| getProcessAffinityMask = kernel32.NewProc("GetProcessAffinityMask") |
| ) |
| |
| // Returns bit count of 1, used by NumCPU |
| func popcnt(x uint64) (n byte) { |
| x -= (x >> 1) & 0x5555555555555555 |
| x = (x>>2)&0x3333333333333333 + x&0x3333333333333333 |
| x += x >> 4 |
| x &= 0x0f0f0f0f0f0f0f0f |
| x *= 0x0101010101010101 |
| return byte(x >> 56) |
| } |
| |
| 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 |
| } |