From owner-freebsd-smp  Thu Jun 21  6:51: 1 2001
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Date: Thu, 21 Jun 2001 23:49:04 +1000 (EST)
From: Bruce Evans <bde@zeta.org.au>
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To: Martin Blapp <mb@imp.ch>
Cc: smp@FreeBSD.ORG, Brad Karp <bkarp@icsi.berkeley.edu>,
	phk@FreeBSD.ORG
Subject: RE: clock speedup on SMP boxes
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On Thu, 21 Jun 2001, Martin Blapp wrote:

> Just gettimeofday() produces 8sec time drifting now. No need
> to use poll() in our little programm I sent previously.
> 
> There is no time drifting if we used a 100% load programm with
> just poll().
> 
> Very strange. Do you have some idea ?

From clock.c in -current:

| #ifdef APIC_IO
| #define	lapic_irr1	((volatile u_int *)&lapic)[0x210 / 4]	/* XXX XXX */
| 	    /* XXX this assumes that apic_8254_intr is < 24. */
| 	    (lapic_irr1 & (1 << apic_8254_intr))))
| #else
| 	    (inb(IO_ICU1) & 1)))
| #endif

Maybe apic_8254_intr is not < 24.  I think the second XXX comment has
rotted in -current, but it still applies in RELENG_4.

Bruce


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