Re: My problems with stability on -current

On 05/11/2011 04:33, Alexander Motin wrote:
> On 11.05.2011 08:17, Doug Barton wrote:
>> I had an interesting result doing nothing but switching from HPET to
>> LAPIC ... no crash. Still on the same version of -current (r221566) the
>> only thing I've done is to add kern.eventtimer.timer="LAPIC" to
>> /boot/loader.conf, and so far I haven't been able to get it to crash no
>> matter how much I compile, or how much other stuff I do in the
>> background. I _can_ get the system heavily loaded enough so that the
>> mouse can drag across the screen, windows take visible time to repaint,
>> etc. That happens with a load average of 4+ on this core 2 duo. But
>> other than that (which is not altogether unreasonable) the system has
>> been very stable for a couple of days now.
>>
>> Does that suggest a next step in terms of what to test?
>
> The fact that LAPIC is working fine can mean that problem is either HPET
> specific or non-per-CPU timers specific. To check that you could try to
> use i8254 timer in one-shot mode:
> hint.attimer.0.timecounter=0
> kern.eventtimer.timer="i8254"
>
> , or use HPET in per-CPU mode:
> hint.atrtc.0.clock=0
> hint.attimer.0.clock=0
> hint.hpet.X.legacy_route=1
>
> But the most informative would be to see what's going on with HPET
> interrupts during the freezes. With HPET hardware it is very easy to
> loose interrupt. And the lost interrupt means problem for many things.
> There are some workarounds made for that, but I can't be sure. For that
> case you could experiment with this patch:
> --- acpi_hpet.c.prev 2010-12-25 11:28:45.000000000 +0200
> +++ acpi_hpet.c 2011-05-11 14:30:59.000000000 +0300
> _at__at_ -190,7 +190,7 _at__at_ restart:
> bus_write_4(sc->mem_res, HPET_TIMER_COMPARATOR(t->num),
> t->next);
> }
> - if (fdiv < 5000) {
> + if (1 || fdiv < 5000) {
> bus_read_4(sc->mem_res, HPET_TIMER_COMPARATOR(t->num));
> now = bus_read_4(sc->mem_res, HPET_MAIN_COUNTER);

FYI, I have been running this patch since you sent it, and haven't 
crashed under high load since.

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