- Don't define DETECT_DEADLOCK. I don't know that this code has detected

a deadlock in several years.  Furthermore, the IPI code is currently
   protected by a seperate spinlock.  This only served to make IPIs twice as
   expensive as they had to be which severely slowed down the IPI heavy ULE
   scheduler.

sys/i386/i386/local_apic.c

@@ -638,7 +638,6 @@ SYSINIT(apic_setup_io, SI_SUB_INTR, SI_ORDER_SECOND, apic_setup_io, NULL)
  * private the sys/i386 code.  The public interface for the rest of the
  * kernel is defined in mp_machdep.c.
  */
-#define DETECT_DEADLOCK
 
 int
 lapic_ipi_wait(int delay)