Messages in this thread | | | Date | Tue, 22 Jul 2008 08:19:25 -0600 | From | Michal Hocko <> | Subject | Re: Why is /sys/class/power_supply/CMB1/energy_now not exported? |
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On Tue, Jul 22, 2008 at 09:49:03AM +0400, Alexey Starikovskiy wrote: > It looks like you use current_now as power, not multiplying it by voltage.
You are right, my calculation are simply wrong. I have mixed remaining capacity (calculated for 2.6.25-2 and 2.6.26) with remaining capacity and some nonsense for the first 2.6.25 (table below was updated).
Nevertheless, what can be the reason for such a different result for distrbution kernel?
> You should either not multiply anything, then you have similar units -- charge and current, > or multiply _both_ by voltage_now, then again you have similar units -- power and energy. > In these both cases you'll have hours or remaining capacity. > [...] >> >> I have tried 3 configurations: >> * 2.6.25 - Vanilla kernel with config-2.6.25 config and result output in >> powertop-2.6.25-good >> * 2.6.25-2 - Debian distribution kernel with config-2.6.25-2 config and >> powertop-2.6.25-2-bad output >> * 2.6.26 - Vanilla kernel with config-2.6.26 config and result output in >> powertop-2.6.26-good >> >> with the following scenario (powertop patched with attached >> charge-read.patch): >> * wait for /sys/class/power_class/CMB1/status FULL on AC >> * get values from all files in ..CMB1 to output file >> * unplug AC >> * run powertop >> * get values from all files in CMB1 again to the same file >> * get output of power consumption to the output file >> >> >> | 2.6.25 2.6.25-2 2.6.26 >> =========================================================================== >> voltage_now | 12222000 12206000 12218000 >> charge_now | 4850000 4850000 4850000 >> current_now | 1398000 1334000 1313000 >> --------------------------------------------------------------------------- >> reported | 16.6 1.4 16.3 >> consumption | >> --------------------------------------------------------------------------- reported | 3.5 41.7 3.6 capacity | --------------------------------------------------------------------------- calculated | 3.46 3.63 3.69 capacity | =========================================================================== [...]
-- Michal Hocko
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