delayed switching

[Hideo S. <sa...@de...>]

Hi Paul,

When I measured a performance with task switching, unexpected delay is issued sometimes. I think that the cause is in idle task so that any interrupt should be blocked in order to halt exclusively.

--- arch/sh/kernel/process.c.org	Thu May 10 10:34:17 2007
+++ arch/sh/kernel/process.c	Thu May 10 10:36:07 2007
@@ -52,18 +52,24 @@ void cpu_idle(void)
 {
 	/* endless idle loop with no priority at all */
 	while (1) {
 		void (*idle)(void) = pm_idle;
 
 		if (!idle)
 			idle = default_idle;
 
-		while (!need_resched())
+		set_bl_bit();
+		for (;;) {
+			if (need_resched()) {
+				clear_bl_bit();
+				break;
+			}
 			idle();
+		}
 
 		preempt_enable_no_resched();
 		schedule();
 		preempt_disable();
 	}
 }
 
 void machine_restart(char * __unused)