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/*
#cgo LDFLAGS:
#include <stdlib.h>
#include <limits.h>
#include <sys/sysctl.h>
#include <sys/mount.h>
#include <mach/mach_init.h>
#include <mach/mach_host.h>
#include <mach/host_info.h>
#if TARGET_OS_MAC
#include <libproc.h>
#endif
#include <mach/processor_info.h>
#include <mach/vm_map.h>
*/
import "C"
func getcpu() error {
var (
count C.mach_msg_type_number_t
cpuload *C.processor_cpu_load_info_data_t
ncpu C.natural_t
)
status := C.host_processor_info(C.host_t(C.mach_host_self()),
C.PROCESSOR_CPU_LOAD_INFO,
&ncpu,
(*C.processor_info_array_t)(unsafe.Pointer(&cpuload)),
&count)
if status != C.KERN_SUCCESS {
return fmt.Errorf("host_processor_info error=%d", status)
}
// jump through some cgo casting hoops and ensure we properly free
// the memory that cpuload points to
target := C.vm_map_t(C.mach_task_self_)
address := C.vm_address_t(uintptr(unsafe.Pointer(cpuload)))
defer C.vm_deallocate(target, address, C.vm_size_t(ncpu))
// the body of struct processor_cpu_load_info
// aka processor_cpu_load_info_data_t
var cpuTicks [C.CPU_STATE_MAX]uint32
// copy the cpuload array to a []byte buffer
// where we can binary.Read the data
size := int(ncpu) * binary.Size(cpuTicks)
buf := (*[1 << 30]byte)(unsafe.Pointer(cpuload))[:size:size]
bbuf := bytes.NewBuffer(buf)
for i := 0; i < int(ncpu); i++ {
err := binary.Read(bbuf, binary.LittleEndian, &cpuTicks)
if err != nil {
return err
}
for k, v := range map[string]int{
"user": C.CPU_STATE_USER,
"system": C.CPU_STATE_SYSTEM,
"nice": C.CPU_STATE_NICE,
"idle": C.CPU_STATE_IDLE,
} {
... // do something with float64(cpuTicks[v])/ClocksPerSec
}
}
return nil
}
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