Re: Since 2.3.20: APIC timer calibration race + patch

Maciej W. Rozycki (macro@ds2.pg.gda.pl)
Fri, 17 Dec 1999 09:57:24 +0100 (MET)


On Fri, 17 Dec 1999, Keith Owens wrote:

> I hoped that patch would fix the APIC errors on my ABIT BP6
> motherboard, alas they still occur in 2.3.33-smp with the 8254 patch,
> compiled with gcc 2.7.2.3. So the BP6 problem is still outstanding.

The patch fixes APIC timer interrupt calibration problems. With this
patch the most visible effect is that you should always get correct CPU
and APIC clock MHz rates printed after "calibrating APIC timer ... " upon
startup. The most important but less obvious effect is the correct timer
tick rate (the tick is obtained from the local APIC timer on SMP systems).

If you get APIC errors then most probably you have a motherboard that
works under marginal conditions (overclocking?). I have yet to see a
single APIC error on my good old Pentium board (beside these caused by my
crazy programs poking at non-existent APIC registers).

-- 
+  Maciej W. Rozycki, Technical University of Gdansk, Poland   +
+--------------------------------------------------------------+
+        e-mail: macro@ds2.pg.gda.pl, PGP key available        +

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