How set process to a CPU using Go in windows? - windows

Question

I want set a process to a CPU using Go in win7, the below code:
package main
import (
"fmt"
"math"
"runtime"
"syscall"
"unsafe"
)
func SetAffinity(pid int, mask *int64) {
syscall.Syscall(syscall.SYS_SCHED_SETAFFINITY,
uintptr(pid), 8, uintptr(unsafe.Pointer(mask)))
}
func GetAffinity(pid int, mask *int64) {
syscall.Syscall(syscall.SYS_SCHED_GETAFFINITY,
uintptr(pid), 8, uintptr(unsafe.Pointer(mask)))
}
var cpuNum = float64(runtime.NumCPU())
var setx = []struct {
args int
expected int64
}{
{0, int64(math.Pow(2, cpuNum)) - 2},
}
func main() {
for _, ca := range setx {
var cpuSet int64
GetAffinity(ca.args, &cpuSet)
cpuSet = cpuSet & 0XFFFFFFE
SetAffinity(ca.args, &cpuSet)
fmt.Println(cpuSet)
GetAffinity(ca.args, &cpuSet)
fmt.Println(cpuSet)
}
}
When I use go run affinity.go, get the follow info:
# command-line-arguments
.\affinity.go:12: undefined: syscall.SYS_SCHED_SETAFFINITY
.\affinity.go:13: not enough arguments in call to syscall.Syscall
.\affinity.go:17: undefined: syscall.SYS_SCHED_GETAFFINITY
.\affinity.go:18: not enough arguments in call to syscall.Syscall
I find SYS_SCHED_SETAFFINITY that it only used in linux.
So, I want to set a process to a cpu using Go in Windows(Win7), what can I do?

Answer 1

You'll have to invoke the WinAPI SetProcessAffinityMask.
Something like this should work:
func setProcessAffinityMask(h syscall.Handle, mask uintptr) (err error) {
r1, _, e1 := syscall.Syscall(syscall.NewLazyDLL("kernel32.dll").NewProc("SetProcessAffinityMask").Addr(), 2, uintptr(h), mask, 0)
if r1 == 0 {
if e1 != 0 {
err = error(e1)
} else {
err = syscall.EINVAL
}
}
return
}
h being the process handle, and mask being the desired affinity mask, of course.
This is taken from Go benchmarks, under the BSD license.