From owner-freebsd-hackers  Thu Aug 30  8: 9: 9 2001
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Date: Thu, 30 Aug 2001 17:14:33 +0200 (CEST)
From: Martin Blapp <mb@imp.ch>
To: Bruce Evans <bde@zeta.org.au>
Cc: <bkarp@icsi.berkeley.edu>, <kpielorz@tdx.co.uk>,
	<sthaug@nethelp.no>, <atrn@zeta.org.au>, <roberto@eurocontrol.fr>,
	<drussell@saturn-tech.com>, <phk@FreeBSD.ORG>,
	<Patrick.Guelat@imp.ch>, <freebsd-hackers@FreeBSD.ORG>,
	<freebsd-smp@FreeBSD.ORG>
Subject: Re: Clock speedup on 4.X FreeBSD SMP and serverworks chipset
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Hi,

Together with Thomas Moestel, I have found that the following patch
seems to solve the gettimeofday() problem and stops the time drift:

--- sys/i386/isa/clock.c        Thu Aug 30 17:01:31 2001
+++ sys/i386/isa/clock.c.new    Thu Aug 30 17:01:29 2001
@@ -1203,7 +1203,7 @@
        high = inb(TIMER_CNTR0);
        count = timer0_max_count - ((high << 8) | low);
        if (count < i8254_lastcount ||
-           (!i8254_ticked && (clkintr_pending ||
+           (!i8254_ticked && (/*clkintr_pending || */
            ((count < 20 || (!(ef & PSL_I) && count < timer0_max_count /
2u)) &&
 #ifdef APIC_IO
 #define        lapic_irr1      ((volatile u_int *)&lapic)[0x210 / 4]   /*
XXX XXX */

We are looking now why this happens.

Bruce: I've looked once what value of apic_8254_intr and it was
below 24. I'll dicuss your change with Thomas and see if that
makes the same diff as our patch.

Martin


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