[indiana-discuss] b111a: Power Management and nwam-issue ?

[Mark Haywood]

Brock Pytlik wrote:
> Mark Haywood wrote:
>> Brock Pytlik wrote:
>>> [snip]
>>> Thanks, that made a huge difference. I'm now spending about 65-70% 
>>> of time in C1 (down from 80%), but now I'm seeing my P-states change 
>>> instead of being pegged at 2531Mhz. When I'm essentially idling, I'm 
>>> @ 800Mhz, and popping up to higher P states periodically.
>>
>> That seems like a lot of time to be spending in C0. Is your system 
>> supposed to be essentially idle? I see a lot of wakeups due to audiohd?
>>
> Yeah, I'm not sure why audiohd is firing that much. I was "idle" not 
> idle. I had a few apps running, firefox, thunderbird, pidgin if I 
> remember right, but nothing that was taxing the machine in any 
> meaningful way. Whatever it was though apparently went away b/c I'm 
> now at 88% in C1 and audiohd isn't showing up at all in that list. I'm 
> not sure why it was in the first place.

Hmm. event-mode might work for you now then.

>>>
>>>
>>> One other thing I'm noticing that seems suspicious is that my 
>>> percentage is always at 100% for one P state. It seems somewhat 
>>> unlikely (to me at least) that it's changing P states exactly on 
>>> every 5 second interval that powertop's using to sample. Is it 
>>> possible that the percentage isn't doing quite what's expected?
>>
>> This doesn't surprise me all that much. In poll-mode the P-State 
>> transitions are much less frequent. You probably won't see them 
>> change often at all unless you either go from being idle to pretty 
>> busy or from busy to idle. In event-mode you should see transitions 
>> many times a second even on a somewhat idle system.
>>
> Well, I guess I expected that the percentage being reported was the 
> percent of time (roughly) spent in that P-state during the last 
> sampling interval (5 seconds). So, when I taxed the machine and made 
> it jump from 800Mhz to 2531Mhz, I was surprised that during that 
> interval, the percentage was still 100%. For example if I started 
> taxing the machine 2.5 seconds after the last refresh, I would've 
> expected 50% @ 800Mhz and 50% @ 2531Mhz. Perhaps I'm just 
> misunderstanding the meaning of the number I'm seeing, but that's what 
> this sentence from the man page would lead me to believe:
> The tool analyzes system activity periodically and  displays a  
> summary  of  how  long the processor is executing at each supported 
> power state.

No. I think you have it right. I just figured you might have misses the 
5 second window where it jumped. Maybe one of the powertop experts will 
jump into with their opinion on this.

Mark

>
> Thanks,
> Brock
>> Mark
>>
>>>
>>> Brock
>