Re: [PATCH] Updated: Dynamic Tick version 050408-1 - C-state measures

Thomas Renninger
2005-04-21T07:54:23Z

Tony Lindgren wrote:
> * Pavel Machek <pavel@suse.cz> [050419 14:10]:
>>Hi!
>>
>>>The machine is a Pentium M 2.00 GHz, supporting C0-C4 processor power states.
>>>The machine run at 2.00 GHz all the time.
>>..
>>>_passing bm_history=0xFFFFFFFF (default) to processor module:_
>>>
>>>Average current the last 470 seconds: *1986mA* (also measured better
>>>values ~1800, does battery level play a role?!?)
>>Probably yes. If voltage changes, 2000mA means different ammount of power.
>
> Thomas, thanks for doing all the stats and patches to squeeze some
> real power savings out of this! :)
>
> We should display both average mA and average Watts with pmstats.
> BTW, I've posted Thomas' version of pmstats as pmstats-0.2.gz to
> muru.com also.
>
>>>(cmp. ftp://ftp.suse.com/pub/people/trenn/dyn_tick_c_states/measures_C4_machine/1000_HZ_bm_history_FFFFFFFF)
>>>
>>>
>>>_passing bm_history=0xFF to processor module:_
>>>
>>>Average current the last 190 seconds: *1757mA*
>>>(cmp. ftp://ftp.suse.com/pub/people/trenn/dyn_tick_c_states/measures_C4_machine/1000_HZ_bm_history_FF)
>>>(Usage count could be bogus, as some invokations could not succeed
>>>if bm has currently been active).
>>Ok.
>>
>>>idle_ms == 100, bm_promote_bs == 30
>>>Average current the last 80 seconds: *1466mA*
>>>(cmp.
>>>ftp://ftp.suse.com/pub/people/trenn/dyn_tick_c_states/measures_C4_machine/tony_dyn_tick_processor_idle_100_bm_30)
>>Very nice indeed. That seems like ~5W saved, right? That might give
>>you one more hour of battery life....
>
> Depending on your battery capacity. But looking at the average Watts
> on the first 8 lines of the two stats above:
>
> 1000_HZ_bm_history_FFFFFFFF:
> (21.43 + 23.32 + 23.32 + 21.71 + 21.71 + 23.84 + 23.84 + 22.62) / 8
> = 22.724W
>
> tony_dyn_tick_processor_idle_100_bm_30:
> (16.07 + 16.07 + 16.00 + 16.00 + 16.08 + 16.08 + 16.29 + 16.29) / 8
> = 16.11W
>
> And then comparing these two:
> 22.72 / 16.11 = 1.4103
>
> So according to my calculations this should provide about 1.4 times
> longer battery life compared to what you were getting earlier...
> That is assuming system is mostly idle, of course.
>
Be aware that speedstep was off (2.0 GHz). When CPU frequency is controlled
you won't have that much enhancement anymore ...

Thomas