High load event idl.

[Oliver Pinter]

On 4/29/12, Alexander Motin <mav at freebsd.org> wrote:
> On 04/29/12 15:27, Oliver Pinter wrote:
>> http://oliverp.teteny.bme.hu/freebsd/ktr/
>
> OK. Now there is no dummynet, but I've found there two more things:
>   1. for some reason some acpi_thremal thread seems to consume about
> 0.37s of time every 10s. I have no idea what is this. It's not 0.7 load,
> but still strange at least.
>   2. I suspect another possible synchronization between ehci driver and
> loadavg as result of interrupt sharing between HPET timer used for time
> events and EHCI USB hardware. Not sure what to do about this. Please
> send _verbose_ dmesg to check whether this interrupt sharing is
> unavoidable.
>
>> On 4/29/12, Alexander Motin<mav at freebsd.org>  wrote:
>>> On 04/29/12 15:04, Oliver Pinter wrote:
>>>> Removing dummynet from kernel don't chanage anything, that is releated
>>>> to load average. The loadavg hold to 0.70 +/- 0.2. (single user : sh +
>>>> top)
>>>
>>> New ktr dump?
>>>
>>>> On 4/29/12, Alexander Motin<mav at freebsd.org>   wrote:
>>>>> On 04/29/12 09:09, Ian Smith wrote:
>>>>>> On Sun, 29 Apr 2012 08:17:38 +0300, Alexander Motin wrote:
>>>>>>     >    On 04/29/12 01:53, Oliver Pinter wrote:
>>>>>>     >    >    Attached the ktr file. This is on core2duo P9400 cpu (
>>>>>>     >    >    smbios.system.product="HP ProBook 5310m (WD792EA#ABU)"
>>>>>> ).
>>>>>> The
>>>>>> workload
>>>>>>     >    >    is only a single user boost: sh + top running, but the
>>>>>> load
>>>>>> average is
>>>>>>     >    >    near 0.5.
>>>>>>     >
>>>>>>     >    ktr shows no real load there. But it shows that you are
>>>>>> using
>>>>>> dummynet, that
>>>>>>     >    schedules its runs on every hardclock tick. I believe that
>>>>>> load
>>>>>> you
>>>>>> see is
>>>>>>     >    the result or synchronization between dummynet calls and
>>>>>> loadvg
>>>>>> sampling,
>>>>>>     >    both of which called from hardclock. I think removing
>>>>>> dummynet
>>>>>> from
>>>>>> equation,
>>>>>>     >    should hide this problem and also reduce you laptops power
>>>>>> consumption.
>>>>>>     >
>>>>>>     >    What's about fixing this, it is loadavg sampling algorithm
>>>>>> that
>>>>>> should be
>>>>>>     >    changed. Fixing dummynet to not run on every hardclock tick
>>>>>> would
>>>>>> also be
>>>>>>     >    great.
>>>>>>
>>>>>> Wading in out of my depth, and copying Luigi in case he misses it ..
>>>>>> but
>>>>>> even back in the olden days when HZ defaulted to 100, one was advised
>>>>>> to
>>>>>> use HZ>= 1000 for smooth dummynet traffic shaping dispatch
>>>>>> scheduling.
>>>>>>
>>>>>> I wonder, with the newer clocks and timers, whether there is another
>>>>>> clock that could be used for dummynet scheduling, that would not have
>>>>>> this effect (even if largely cosmetic?) on load average calculation?
>>>>>
>>>>> First of all, the easiest solution would be to make dummynet to
>>>>> schedule
>>>>> callout not automatically, but on first queued packet. I believe that
>>>>> in
>>>>> case of laptop the queue should be empty most of time and the callout
>>>>> calls are completely useless there. Luigi promised to look on this
>>>>> once.
>>>>>
>>>>> What's about better precision/removing synchronization -- there is
>>>>> starting GSoC project now (by davide@) to rewrite callout(9) subsystem
>>>>> to use better precision allowed by new timer drivers. While now it is
>>>>> possible to get raw access to additional timer hardware available on
>>>>> some systems, I don't think it is a good idea.

http://freebsd.1045724.n5.nabble.com/amd64-160419-acpi-thermal-kernel-thread-high-CPU-usage-td4765266.html

but this "high cpu load" is gone, releated to acpi_thermal in 2011 september

>
>
> --
> Alexander Motin
>