System extremely slow under light load

[Alexandre Kovalenko]

On Apr 25, 2011 6:28 AM, "Ian Smith" <smithi at nimnet.asn.au> wrote:
>
> On Mon, 25 Apr 2011, Bartosz Fabianowski wrote:
>  [Jeremy wrote:]
>  > > As the processor gets hotter, internal clocks and so on are throttled
>  > > within the hardware to try and stabilise the temperature (to keep the
>  > > thermal trip point being reached, re: "emergency shutdown"), which
>  > > greatly decreases performance.  I'm not sure if there's a way to
>  > > detect this, but I would hope (?) that it would be visible via the
>  > > CPU clock frequency (on FreeBSD this would be sysctl
>  > > dev.cpu.X.freq).
>  >
>  > sysctl dev.cpu.X.freq is used to set the frequency. I have not found
any
>  > way to read back its internal state so far.
>
> dev.cpu.X.freq does reflect the current frequency; I don't know whether
> or how any internal clock throttling might be exposed.
>
> Jeremy's right, it's running very hot, probably 20C too hot.  I was just
> going to mention a couple of things you could try when it began to seem
> all too familiar .. a bit of hunting found your previous overheating
> problems on a Dell Studio 1557 from April last year:
>
> http://lists.freebsd.org/pipermail/freebsd-acpi/2010-April/006415.html
>
> and your eventual apparent solution which included some fiddling with
> thermal parameters but primarily by disabling p4tcc and acpi_throttle
>
> hint.p4tcc.0.disabled="1"
> hint.acpi_throttle.0.disabled="1"
>
> in loader.conf; I'm surprised you haven't tried that again on this one?
>
>  > hw.acpi.cpu.cx_lowest: C1
>
> See below.
>
>  > hw.acpi.thermal.min_runtime: 0
>  > hw.acpi.thermal.polling_rate: 10
>  > hw.acpi.thermal.user_override: 0
>  > hw.acpi.thermal.tz0.temperature: 26.8C
>  > hw.acpi.thermal.tz0.active: -1
>  > hw.acpi.thermal.tz0.passive_cooling: 0
>  > hw.acpi.thermal.tz0.thermal_flags: 0
>  > hw.acpi.thermal.tz0._PSV: -1
>  > hw.acpi.thermal.tz0._HOT: -1
>  > hw.acpi.thermal.tz0._CRT: 100.0C
>  > hw.acpi.thermal.tz0._ACx: 71.0C 55.0C -1 -1 -1 -1 -1 -1 -1 -1
>  > hw.acpi.thermal.tz0._TC1: -1
>  > hw.acpi.thermal.tz0._TC2: -1
>  > hw.acpi.thermal.tz0._TSP: -1
>
> tz0 looks to be a fan.  It seems unlikely that any temp. sensor inside a
> machine with CPU temp. at 82C could possibly be as low as 26.8C, so this
> value is likely as bogus as the 0.0C CPU reported by tz1.

I am not sure tz0 is the real thermal zone, especially given values of _tc1,
_tc2 and _tsp. Temperature value (3001)  looks suspicious as well. Can you,
by any chance, put your ASL someplace accessible and provide a description
of what you have done to fix the temperature reporting.

As the side note: I have seen and do own pieces of equipment that use
thermal zones to initiate critical shutdown for various and unrelated
reasons.