Re: [Dynamicpower-devel] DPM questions

[Todd P. <tp...@mv...>]

Daniel Petrini wrote:

> -How can I assign an user process to a operating state (task-4,
> task-3...task, task+3, task+4)? Reading /proc/driver/dpm/stats I see
> that the system only switches among idle, idle-task and task.  How can
> I start a process  in task-4 state for instance?

Hi Daniel -- In newer code write a task state name to /proc/<pid>/dpmstate:

# echo -n "task-4" > /proc/$$/dpmstate
# ls
# cat /sys/dpm/state/stats
state: idle-task ticks: 1996910 times: 13591
state: idle ticks: 749169144 times: 13385
state: sleep ticks: 0 times: 0
state: task-4 ticks: 1287414 times: 121
...

Using older patches there's another, now-deprecated, interface for it:

# echo "set_task_state $$ -4" > /proc/driver/dpm/cmd

> -Is there any user level application or deamon that runs and manage
> the task assignment, a test policy manager already developed?

A number of folks have developed application software to manage DPM for 
their consumer product needs or as a developer tool in Linux development 
platform product, not sure specifically whether any features regarding 
task state assignments have been developed, and I don't know that 
anything is available for general use.  If you have ideas on what might 
be needed for managing task assignments I'm open to suggestions.

> -Which are the operating points parameters: tc_rate, mpuper_rate and dsp_rate?

OMAP power parameters "tc-div", "per-div", and "dsp-div" refer to the 
clock divisors that may be set in the ARM CKCTL for these components... 
the rate associated with these would normally refer to a value computed 
in conjunction with settings of other upstream clocks (that are divided 
down per those parameters).

Hope that helps,


-- 
Todd