Messages in this thread | | | Subject | Re: [PATCH 1/1] SGI X86 UV: Provide a System Activity Indicator driver | From | Andi Kleen <> | Date | Fri, 24 Oct 2008 20:12:38 +0200 |
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Mike Travis <travis@sgi.com> writes: > > I do use the timer mechanism (once per second) to update the scir state. > Unfortunately, the state is *always* not idle during the timer callback > (since we are actively executing), so I needed some way of knowing the > idle state prior to the timer callback.
The idle thread always has pid 0. So if the timer sees current->pid == 0 it interrupted idle.
But sampling only once a second would be presumably not very accurate. You could just check the per cpu statistics the kernel keeps anyways in the timer.
I agree with Ingo that this doesn't belong in a idle notifier.
-Andi -- ak@linux.intel.com
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