Hello List,
I am trying to get throttling to work on the following processor with
linux 2.6.17-1.2142_FC4
with no luck.
AMD Athlon(tm) XP 1700+
cat /proc/acpi/processor/CPU0/info
processor id: 0
acpi id: 0
bus mastering control: no
power management: yes
throttling control: yes
limit interface: yes
The /sys/devices/system/cpu/cpu0/cpufreq/* directory does not exist. I
have modprobed
the following cpufreq* modules.
Module Size Used by
cpufreq_stats 6101 0
cpufreq_powersave 2241 0
cpufreq_ondemand 7009 0
cpufreq_conservative 7265 0
What am I doing wrong?
Thanks Steve
--
"They that give up essential liberty to obtain temporary safety,
deserve neither liberty nor safety." (Ben Franklin)
"The course of history shows that as a government grows, liberty
decreases." (Thomas Jefferson)
On Mon, Nov 19, 2007 at 07:41:31PM -0500, Stephen Clark wrote:
> Hello List,
>
> I am trying to get throttling to work on the following processor
I think by throttling, you actually mean changing frequency/voltage ?
(throttling is something else, where the CPU skips every n cycles,
which doesn't actually save any power)
> with linux 2.6.17-1.2142_FC4 with no luck.
wow. that's a prehistoric kernel.
> AMD Athlon(tm) XP 1700+
you lose. Only the mobile athlons supported scaling their speed.
And even then, only if the BIOS supported it with the correct tables.
(Typically this means, "only laptops").
Dave
--
http://www.codemonkey.org.uk
Dave Jones wrote:
>On Mon, Nov 19, 2007 at 07:41:31PM -0500, Stephen Clark wrote:
> > Hello List,
> >
> > I am trying to get throttling to work on the following processor
>
>I think by throttling, you actually mean changing frequency/voltage ?
>(throttling is something else, where the CPU skips every n cycles,
> which doesn't actually save any power)
>
> > with linux 2.6.17-1.2142_FC4 with no luck.
>
>wow. that's a prehistoric kernel.
>
> > AMD Athlon(tm) XP 1700+
>
>you lose. Only the mobile athlons supported scaling their speed.
>And even then, only if the BIOS supported it with the correct tables.
>(Typically this means, "only laptops").
>
> Dave
>
>
>
well what about the info from /proc/
cat /proc/acpi/processor/CPU0/info
processor id: 0
acpi id: 0
bus mastering control: no
power management: yes
throttling control: yes
limit interface: yes
and:
cat /proc/acpi/processor/CPU0/throttling
state count: 2
active state: T0
states:
*T0: 00%
T1: 50%
and:
[root@joker ~]# cat /proc/acpi/processor/CPU0/power
active state: C2
max_cstate: C8
bus master activity: d18324c9
states:
C1: type[C1] promotion[C2] demotion[--]
latency[000] usage[01340140]
*C2: type[C2] promotion[--] demotion[C1]
latency[090] usage[02980043]
????
Steve
--
"They that give up essential liberty to obtain temporary safety,
deserve neither liberty nor safety." (Ben Franklin)
"The course of history shows that as a government grows, liberty
decreases." (Thomas Jefferson)
On Mon, Nov 19, 2007 at 08:05:29PM -0500, Stephen Clark wrote:
> >I think by throttling, you actually mean changing frequency/voltage ?
> >(throttling is something else, where the CPU skips every n cycles,
> > which doesn't actually save any power)
> >
> well what about the info from /proc/
>
> cat /proc/acpi/processor/CPU0/info
> processor id: 0
> acpi id: 0
> bus mastering control: no
> power management: yes
> throttling control: yes
> limit interface: yes
>
> and:
> cat /proc/acpi/processor/CPU0/throttling
> state count: 2
> active state: T0
> states:
> *T0: 00%
> T1: 50%
See above. These are throttling states, used typically
if the system is overheating.
> [root@joker ~]# cat /proc/acpi/processor/CPU0/power
> active state: C2
> max_cstate: C8
> bus master activity: d18324c9
> states:
> C1: type[C1] promotion[C2] demotion[--]
> latency[000] usage[01340140]
> *C2: type[C2] promotion[--] demotion[C1]
> latency[090] usage[02980043]
>
> ????
C states are unrelated to frequency/voltage scaling (which are P states)
They get taken advantage of automatically by ACPI as you can
see from the usage fields.
Dave
--
http://www.codemonkey.org.uk
Dave Jones wrote:
> >
> > and:
> > cat /proc/acpi/processor/CPU0/throttling
> > state count: 2
> > active state: T0
> > states:
> > *T0: 00%
> > T1: 50%
>
> See above. These are throttling states, used typically
> if the system is overheating.
>
And more importantly, there is no power advantages over T states as
opposed to C states. They pretty much mean pulsing the system in and
out of either C1 or C2 depending on the CPU/chipset.
-hpa
H. Peter Anvin wrote:
> And more importantly, there is no power advantages over T states as
> opposed to C states. They pretty much mean pulsing the system in and
> out of either C1 or C2 depending on the CPU/chipset.
Well, they FORCE the use of the C states to save power, even if the
kernel doesn't want to because it still has runnable tasks. This can be
useful if you know you are running a task that busy waits but would not
suffer from having the performance of the cpu cut in half. Since it is
busy waiting, the kernel never activates the C states, but the
throttling will force it and thus, save you power and heat.