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kang

Member

Registered: 2010-08-07

Posts: 83

[SOLVED] Tracking down intel pc states

I'm trying to figure out which part of the hardware keeps my laptop above pc3 (haswell, i7 4500). I can't find much doc on that and wondered if there were any tips...
On Windows, it goes to pc3 just fine.

Sample (system is pretty much idle/nothing running):

 sudo turbostat sleep 60
    Core     CPU Avg_MHz   %Busy Bzy_MHz TSC_MHz     SMI  CPU%c1  CPU%c3  CPU%c6  CPU%c7 CoreTmp  PkgTmp Pkg%pc2 Pkg%pc3 Pkg%pc6 Pkg%pc7 Pkg%pc8 Pkg%pc9 Pk%pc10 PkgWatt CorWatt GFXWatt 
       -       -      67    3.72    1798    2394       0   11.85    1.05    0.70   82.68      53      53   75.64    0.00    0.00    0.00    0.00    0.00    0.00    3.68    0.43    0.03
       0       0      92    4.88    1880    2394       0   11.74    0.94    0.78   81.66      51      53   75.64    0.00    0.00    0.00    0.00    0.00    0.00    3.68    0.43    0.03
       0       2      63    3.52    1792    2394       0   13.11
       1       1      64    3.68    1734    2394       0   10.83    1.16    0.63   83.70      53
       1       3      49    2.79    1745    2394       0   11.72
60.001607 sec

CPU is correctly spending most of its time in C7 (and core watts is low) , and GPU is correctly in in RC6 (0.03 watts).
However, its most spending time in pc2 and pkgwatt is still relatively high.
System temperature is also about 8C higher than in Windows.
PCIE ASPM is on.

powertop doesn't report anything odd except that the total discharge rate is around 7w instead of 3.5w (windows) when fully idle.
Same result on the LTS and latest (3.16) kernels.

Any idea?

Last edited by kang (2014-09-16 17:54:42)

kang

Member

Registered: 2010-08-07

Posts: 83

Re: [SOLVED] Tracking down intel pc states

turns out, powertop is more accurate than I thought. Well, that'll teach me
iwlwifi showed high wattage.
turns out the automatic powersave feature doesn't work the way i expected it to.

i set it manually via iw dev <device> set power_save on

bang!

    Core     CPU Avg_MHz   %Busy Bzy_MHz TSC_MHz     SMI  CPU%c1  CPU%c3  CPU%c6  CPU%c7 CoreTmp  PkgTmp Pkg%pc2 Pkg%pc3 Pkg%pc6 Pkg%pc7 Pkg%pc8 Pkg%pc9 Pk%pc10 PkgWatt CorWatt GFXWatt                           
       -       -      15    1.14    1316    2394       0    5.94    0.08    0.10   92.73      40      40    3.84    0.12    0.13   82.68    0.00    0.00    0.00    0.59    0.05    0.02                           
       0       0      23    1.84    1225    2394       0    4.88    0.13    0.11   93.05      40      40    3.84    0.12    0.13   82.68    0.00    0.00    0.00    0.59    0.05    0.02                           
       0       2      13    1.03    1305    2394       0    5.69                                                                                                                                                   
       1       1      10    0.71    1424    2394       0    6.75    0.03    0.09   92.42      40                                                                                                                   
       1       3      14    1.00    1416    2394       0    6.46        

here we go, pc3, and up to pc7
package watt is down to 0.6w... total platform to 3/3.5watts as it should be

woot.