[PATCH] ia64: don't call note_interrupt() for per-CPU irqs

The note_interrupt() code is racy for per-CPU irqs and causes severe
performance problems due to cache-line bouncing on large SMPs.  Just don't
call it for that case.

arch/ia64/kernel/irq.c

@@ -465,8 +465,6 @@ unsigned int do_IRQ(unsigned long irq, struct pt_regs *regs)
 		desc->handler->ack(irq);
 		action_ret = handle_IRQ_event(irq, regs, desc->action);
 		desc->handler->end(irq);
-		if (!noirqdebug)
-			note_interrupt(irq, desc, action_ret);
 	} else {
 		spin_lock(&desc->lock);
 		desc->handler->ack(irq);