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Date: Sat, 07 Dec 2002 13:29:35 -0500
From: Jim Houston <jim.houston@attbi.com>
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To: Mika =?iso-8859-1?Q?Penttil=E4?= <mika.penttila@kolumbus.fi>
CC: linux-kernel@vger.kernel.org,
       high-res-timers-discourse@lists.sourceforge.net
Subject: Re: [PATCH] The alternate Posix timers patch7
References: <200212071713.gB7HDdv09557@linux.local> <3DF231E8.60703@kolumbus.fi>
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Mika Penttil? wrote:
> 
> Just out of curiosity, how does the "sharing the local APIC timer" work
> with the SMP local APIC timer scheme. Hopefully not disable periodic
> timer tick on that cpu totally...?
> 
> --Mika

Hi Mike,

Here is how I wire into the timer interrupt:

   inline void smp_local_timer_interrupt(struct pt_regs * regs)
   {
        int cpu = smp_processor_id();
 
	if (!run_posix_timers((void *)regs))
                return;
        ... the original code continues.

I keep an in kernel Posix style timer queued for each cpu at
HZ frequency.  If this timer has expired run_posix_timers returns
true and the normal local timer processing is done.

The code is not perfect yet.  I don't honour changes in the 
profiling multiplier.

Jim Houston - Concurrent Computer Corp.
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