5:33 p.m.
Hi All,
I am working on research related to Power management and control for single
and multiprocessors and I came across ACPI standard. I want to get all CPU
power information (c state and frequency p state information) for different
applications and kernel processes running into system (with load). I went
through user manual of the ACPI and as per my understaning there is some
information written by the ACPI HW/SW module and ACPI is already a part of
most Linux kernels.I went through all the acpi site but there is no sample
program to show its usage also i have installed the UNIX Format Source Code
and Build Environment
<http://www.acpica.org/downloads/unix_source_code.php>and UNIX
Format Test Suite <http://www.acpica.org/downloads/unix_test_suite.php> of
the ACPI and successfully compiled it. I am not sure how and which acpi APIs
needs to be called to get such information and how to install the ACPI
library...Also I want to control CPU frquency and state not sure how to
achieve it using ACPI library?
I am using an environment with Intel Dual Core Tm processor and Ubuntu
platform.
Thanks and Regards,
- Nisha
12:16 p.m.
On Wed, 23 Dec 2009, nisha jain wrote:
Hi All,
I am working on research related to Power management and control for single and
multiprocessors and I came across ACPI standard. I want
to get all CPU power information (c state and frequency p state information) for
different applications and kernel processes running
into system (with load). I went through user manual of the ACPI and as per my
understaning there is some information written by the
ACPI HW/SW module and ACPI is already a part of most Linux kernels.I went through all the
acpi site but there is no sample program to
show its usage also i have installed the UNIX Format Source Code and Build Environment
and UNIX Format Test Suite of the ACPI and
successfully compiled it. I am not sure how and which acpi APIs needs to be called to get
such information and how to install the ACPI
library...Also I want to control CPU frquency and state not sure how to achieve it using
ACPI library?
I am using an environment with Intel Dual Core Tm processor and Ubuntu platform.
Hi Nisha,
ACPI is an interface between the hardware and the OS,
not an interface between the kernel and user-space.
So generally the ACPICA core is hidden inside the kernel
and not directly visible to user-space.
So your question is really about the Linux APIs for
user-space utilities to get to the stuff that is
implemented by ACPI.
On Linux, we endeavor to expose ACPI directly to application layer
only for debugging hooks -- eg the old /proc/acpi/*
and the new /sys/firmware/acpi/*
In general, we try to have generic policy code that doesn't
directly know if ACPI is involved in the underlying implementation.
For example, cpufreq abstracts ACPI P-states, cpuidle
abstracts ACPI C-states, thermal abstracts ACPI thermal & T-states,
power supply abstracts ACPI battery etc.
Note that the powertop application is available in most recent distros
to grab and summarize a lot of what you may be seeking.
It looks in /sys/devices/system/cpu/* for cpufreq and cpuidle info.
cheers,
-Len Brown
Intel Open Source Technology Center
1:06 p.m.
Hi Len,
Thanks, I have tried using the PowerTop application and modified to see it
for dual core but i am not able to get the proper results (c state
information for second core is not proper) also I have found through the
PowerTop developers that the application is not suitable for full load power
measurement. I am not quite sure what does the idle mode means though i
think it means that no user level applications are running. I am not able to
further use the PowerTop as it doesn't provide mechanism for changing the
processor state by user and I guess there are only few utilities for doing
frequency scaling like cpfreq-set utility, I need to develop customized
utility. I would like to know how I can develop my own utility using ACPI if
it is feasible? Also if any specific development environment is required to
do so?
Thanks and Regards,
Nisha
On Thu, Dec 24, 2009 at 2:16 PM, Len Brown <lenb(a)kernel.org> wrote:
On Wed, 23 Dec 2009, nisha jain wrote:
> Hi All,
>
> I am working on research related to Power management and control for
single and multiprocessors and I came across ACPI standard. I want
> to get all CPU power information (c state and frequency p state
information) for different applications and kernel processes running
> into system (with load). I went through user manual of the ACPI and as
per my understaning there is some information written by the
> ACPI HW/SW module and ACPI is already a part of most Linux kernels.I went
through all the acpi site but there is no sample program to
> show its usage also i have installed the UNIX Format Source Code and
Build Environment and UNIX Format Test Suite of the ACPI and
> successfully compiled it. I am not sure how and which acpi APIs needs to
be called to get such information and how to install the ACPI
> library...Also I want to control CPU frquency and state not sure how to
achieve it using ACPI library?
>
> I am using an environment with Intel Dual Core Tm processor and Ubuntu
platform.
Hi Nisha,
ACPI is an interface between the hardware and the OS,
not an interface between the kernel and user-space.
So generally the ACPICA core is hidden inside the kernel
and not directly visible to user-space.
So your question is really about the Linux APIs for
user-space utilities to get to the stuff that is
implemented by ACPI.
On Linux, we endeavor to expose ACPI directly to application layer
only for debugging hooks -- eg the old /proc/acpi/*
and the new /sys/firmware/acpi/*
In general, we try to have generic policy code that doesn't
directly know if ACPI is involved in the underlying implementation.
For example, cpufreq abstracts ACPI P-states, cpuidle
abstracts ACPI C-states, thermal abstracts ACPI thermal & T-states,
power supply abstracts ACPI battery etc.
Note that the powertop application is available in most recent distros
to grab and summarize a lot of what you may be seeking.
It looks in /sys/devices/system/cpu/* for cpufreq and cpuidle info.
cheers,
-Len Brown
Intel Open Source Technology Center
8:03 p.m.
Thanks, I have tried using the PowerTop application and modified to
see it for dual core but i am not able to get the proper results (c
state information for second core is not proper) also I have found through the PowerTop
developers that the application is not suitable
for full load power measurement. I am not quite sure what does the idle mode means though
i think it means that no user level
applications are running. I am not able to further use the PowerTop as it doesn't
provide mechanism for changing the processor state by
user and I guess there are only few utilities for doing frequency scaling like cpfreq-set
utility, I need to develop customized
utility. I would like to know how I can develop my own utility using ACPI if it is
feasible? Also if any specific development
environment is required to do so?
I don't understand what your goal is,
and thus I'm unable to help you reach it.
-Len
9:12 p.m.
Hi Len,
I need to get and control the power consumption of the applications running
in the system. I understand ACPI standard provide the interface for power
management and control. I am trying to understand how i can develop using
ACPI a user space utility to get the power state information and can also
change the frequency and voltage of the cores.
Thanks and Regards,
Nisha
On Fri, Dec 25, 2009 at 10:03 PM, Len Brown <lenb(a)kernel.org> wrote:
> Thanks, I have tried using the PowerTop application and modified
to see
it for dual core but i am not able to get the proper results (c
> state information for second core is not proper) also I have found
through the PowerTop developers that the application is not suitable
> for full load power measurement. I am not quite sure what does the idle
mode means though i think it means that no user level
> applications are running. I am not able to further use the PowerTop as it
doesn't provide mechanism for changing the processor state by
> user and I guess there are only few utilities for doing frequency scaling
like cpfreq-set utility, I need to develop customized
> utility. I would like to know how I can develop my own utility using ACPI
if it is feasible? Also if any specific development
> environment is required to do so?
I don't understand what your goal is,
and thus I'm unable to help you reach it.
-Len
4612
days inactive
4614
days old
4 comments
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participants (2)
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nisha jain