Commit c83e4484 authored May 08, 2007 by Jeff Dike Committed by Linus Torvalds May 08, 2007

uml: an idle system should have zero load average



The ever-vigilant users of linode.com noticed that an idle 2.6 UML has a
persistent load average of ~.4.

It turns out that because the UML timer handler processed softirqs before
actually delivering the tick, the tick was counted in the context of the idle
thread about half the time.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent f1adc05e

arch/um/kernel/time.c

+2 −2

Original line number	Original line	Diff line number	Diff line
	@@ -177,6 +177,8 @@ int do_settimeofday(struct timespec *tv)

	void timer_handler(int sig, union uml_pt_regs *regs)		void timer_handler(int sig, union uml_pt_regs *regs)
	{		{
			if(current_thread->cpu == 0)
			timer_irq(regs);
	local_irq_disable();		local_irq_disable();
	irq_enter();		irq_enter();
	update_process_times(CHOOSE_MODE(		update_process_times(CHOOSE_MODE(
	@@ -184,6 +186,4 @@ void timer_handler(int sig, union uml_pt_regs *regs)
	(regs)->skas.is_user));		(regs)->skas.is_user));
	irq_exit();		irq_exit();
	local_irq_enable();		local_irq_enable();
	if(current_thread->cpu == 0)
	timer_irq(regs);
	}		}

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