x86: improve default idle

Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/process_32.c

@@ -113,16 +113,8 @@ void default_idle(void)
 
 		local_irq_disable();
 		if (!need_resched()) {
-			ktime_t t0, t1;
-			u64 t0n, t1n;
-
-			t0 = ktime_get();
-			t0n = ktime_to_ns(t0);
 			safe_halt();	/* enables interrupts racelessly */
 			local_irq_disable();
-			t1 = ktime_get();
-			t1n = ktime_to_ns(t1);
-			sched_clock_idle_wakeup_event(t1n - t0n);
 		}
 		local_irq_enable();
 		current_thread_info()->status |= TS_POLLING;

arch/x86/kernel/process_64.c

@@ -107,16 +107,8 @@ void default_idle(void)
 	smp_mb();
 	local_irq_disable();
 	if (!need_resched()) {
-		ktime_t t0, t1;
-		u64 t0n, t1n;
-
-		t0 = ktime_get();
-		t0n = ktime_to_ns(t0);
 		safe_halt();	/* enables interrupts racelessly */
 		local_irq_disable();
-		t1 = ktime_get();
-		t1n = ktime_to_ns(t1);
-		sched_clock_idle_wakeup_event(t1n - t0n);
 	}
 	local_irq_enable();
 	current_thread_info()->status |= TS_POLLING;