Re: [question] I doublt on timer interrput.

From: Robert Love
Date: Mon Nov 07 2005 - 11:17:51 EST


On Mon, 2005-11-07 at 14:05 +0800, liyu wrote:
> Hi, all:
>
> I have one question about timer interrupt (i386 architecture).
>
> As we known, the timer emit HZ times interrputs per second,
> and in i386. The interrupt handler will call scheduler_tick()
> each time (on i386 at least, both enable or disable APIC).
>
> On my Celeron machine(IOW, only one CPU, not SMP/SMT), I defined
> a global int variable 'tick_count' in kernel/sched.c, and add one line
> of code like follow in scheduler_tick():
>
> ++tick_count;
>
> but I found it is not same with content of the /proc/interrupts,
> and the differennt between them is not little.
>
> I can not understand why that is.
>
> Any useful idea.

scheduler_tick() is not the timer interrupt.

You want to hook into do_timer() or similar.

Robert Love


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