// accurate reporting of its CPU usage; see issue 35057) and ignore any
		// that it gets from the process-wide setitimer (to not over-count its
		// CPU consumption).
		return timer_create
	}

	// No active per-thread timer means the only valid profiler is setitimer.
	return setitimer
}

func setProcessCPUProfiler(hz int32) {
	setProcessCPUProfilerTimer(hz)
}

	return int32(r)
}

//go:nosplit
func setitimer(mode int32, new, old *itimerval) {
	r, err := syscall3(&libc_setitimer, uintptr(mode), uintptr(unsafe.Pointer(new)), uintptr(unsafe.Pointer(old)))
	if int32(r) == -1 {
		println("syscall setitimer failed: ", hex(err))
		throw("syscall setitimer")
	}
}

//go:nosplit
func malloc(size uintptr) unsafe.Pointer {

//go:cgo_import_dynamic libc_sem_post sem_post "libc.so"
//go:cgo_import_dynamic libc_sem_reltimedwait_np sem_reltimedwait_np "libc.so"
//go:cgo_import_dynamic libc_sem_wait sem_wait "libc.so"
//go:cgo_import_dynamic libc_setitimer setitimer "libc.so"
//go:cgo_import_dynamic libc_sigaction sigaction "libc.so"
//go:cgo_import_dynamic libc_sigaltstack sigaltstack "libc.so"
//go:cgo_import_dynamic libc_sigprocmask sigprocmask "libc.so"

//go:cgo_unsafe_args
func raiseproc(sig uint32) {
	libcCall(unsafe.Pointer(abi.FuncPCABI0(raiseproc_trampoline)), unsafe.Pointer(&sig))
}
func raiseproc_trampoline()

//go:nosplit
//go:cgo_unsafe_args
func setitimer(mode int32, new, old *itimerval) {
	libcCall(unsafe.Pointer(abi.FuncPCABI0(setitimer_trampoline)), unsafe.Pointer(&mode))
	KeepAlive(new)
	KeepAlive(old)
}
func setitimer_trampoline()

//go:nosplit

	// From NetBSD's <sys/ucontext.h>
	_UC_SIGMASK = 0x01
	_UC_CPU     = 0x04

	// From <sys/lwp.h>
	_LWP_DETACHED = 0x00000040
)

type mOS struct {
	waitsemacount uint32
}

//go:noescape
func setitimer(mode int32, new, old *itimerval)

//go:noescape
func sigaction(sig uint32, new, old *sigactiont)

//go:noescape
func sigaltstack(new, old *stackt)

//go:noescape
func sigprocmask(how int32, new, old *sigset)

//go:noescape
func thr_new(param *thrparam, size int32) int32

//go:noescape
func sigaltstack(new, old *stackt)

//go:noescape
func sigprocmask(how int32, new, old *sigset)

//go:noescape
func setitimer(mode int32, new, old *itimerval)

//go:noescape
func sysctl(mib *uint32, miblen uint32, out *byte, size *uintptr, dst *byte, ndst uintptr) int32

func raiseproc(sig uint32)

func thr_self() thread

			setsig(_SIGPROF, abi.FuncPCABIInternal(sighandler))
		}

		var it itimerval
		it.it_interval.tv_sec = 0
		it.it_interval.set_usec(1000000 / hz)
		it.it_value = it.it_interval
		setitimer(_ITIMER_PROF, &it, nil)
	} else {
		setitimer(_ITIMER_PROF, &itimerval{}, nil)

		// If the Go signal handler should be disabled by default,
		// switch back to the signal handler that was installed

	SYS_SETPGID                  = 82  // { int setpgid(int pid, int pgid); }
	SYS_SETITIMER                = 83  // { int setitimer(u_int which, struct \
	SYS_SWAPON                   = 85  // { int swapon(char *name); }
	SYS_GETITIMER                = 86  // { int getitimer(u_int which, \
	SYS_GETDTABLESIZE            = 89  // { int getdtablesize(void); }
	SYS_DUP2                     = 90  // { int dup2(u_int from, u_int to); }

	SYS_SETPGID                  = 82  // { int setpgid(int pid, int pgid); }
	SYS_SETITIMER                = 83  // { int setitimer(u_int which, struct \
	SYS_SWAPON                   = 85  // { int swapon(char *name); }
	SYS_GETITIMER                = 86  // { int getitimer(u_int which, \
	SYS_GETDTABLESIZE            = 89  // { int getdtablesize(void); }
	SYS_DUP2                     = 90  // { int dup2(u_int from, u_int to); }

	RET

// func tgkill(tgid, tid, sig int)
TEXT ·tgkill(SB),NOSPLIT|NOFRAME,$0-24
	MOV	tgid+0(FP), A0
	MOV	tid+8(FP), A1
	MOV	sig+16(FP), A2
	MOV	$SYS_tgkill, A7
	ECALL
	RET

// func setitimer(mode int32, new, old *itimerval)
TEXT runtime·setitimer(SB),NOSPLIT|NOFRAME,$0-24
	MOVW	mode+0(FP), A0
	MOV	new+8(FP), A1
	MOV	old+16(FP), A2
	MOV	$SYS_setitimer, A7
	ECALL
	RET