One-shot-oriented event timers management

[Alexander Motin]

Ian FREISLICH wrote:
> On Wed, Sep 1, 2010 at 2:16 PM, Alexander Motin <mav at freebsd.org> wrote:
>> Brandon Gooch wrote:
>>> This latest patch causes an interrupt storm with the HPET timer on my
>>> system. The machine took about 8 minutes to boot and bring me to a
>>> login prompt. System interactivity (i.e. input from keyboard, output
>>> on console) was fine, but after checking the output of `systat vmstat
>>> -1`, I saw the interrupt rate on each HPET entry was over 120k!
>>>
>>> Can I provide any useful detail? Of course, test patches are always welcom
> e :)
>> I was able to reproduce alike storm in some situations.
>>
>> Try new version: http://people.freebsd.org/~mav/timers_oneshot7.patch
> 
> Interrupt rates are definitely reduced.
> 
> [mini] /usr/home/ianf $ vmstat -i
> interrupt                          total       rate
> irq1: atkbd0                        1154          1
> irq9: acpi0                        10829         15
> irq16: ath0 uhci3+                 16226         23
> irq18: uhci2                          16          0
> irq19: uhci1+                       7090         10
> irq20: hpet0                      169288        240
> irq23: uhci0 ehci0                    64          0
> irq256: hdac0                        187          0
> Total                             204854        291

Nice. But 240 still quite a lot. Have you applied tm6292_idle.patch and
was this system idle at the moment?

> [mini] /usr/home/ianf $ sysctl dev.cpu |grep usage
> dev.cpu.0.cx_usage: 0.00% 0.04% 0.80% 99.15% last 1601us
> dev.cpu.1.cx_usage: 0.00% 0.00% 0.65% 99.34% last 2078us

It is the first time I see in practice system reporting 4 different ACPI
C-states. What is this system? What CPU is there? Could you show me full
`sysctl dev.cpu` output?

-- 
Alexander Motin