On 04/14/2013 11:59 PM, Borislav Petkov wrote: > On Sun, Apr 14, 2013 at 09:28:50AM +0800, Alex Shi wrote: >> Even some scenario the total energy cost more, at least the avg watts >> dropped in that scenarios. > > Ok, what's wrong with x = 32 then? So basically if you're looking at > avg watts, you don't want to have more than 16 threads, otherwise > powersaving sucks on that particular uarch and platform. Can you say > that for all platforms out there?
The cpu freq boost make the avg watts higher with x = 32, and also make higher power efficiency. We can disable cpu freq boost for this if we want lower power consumption all time. But for my understanding, the power efficient is better way to save power. As to other platforms, I'm glad to see any testing or try and give me results... > > Also, I've added in the columns below the Energy = Power * Time thing. Thanks. btw the third data of each column is 'performance/watt'. that shows similar meaning on the other side. :) > > And the funny thing is, exactly there where avg watts is better in > powersaving, energy for workload retire is worse. And the other way > around. Basically, avg watts vs retire energy is reciprocal. Great :-\. > >> Len said he has low p-state which can work there. but that's is >> different. I had sent some data in another email list to show the >> difference: >> >> The following is 2 times kbuild testing result for 3 kinds condiation on >> SNB EP box, the middle column is the lowest p-state testing result, we >> can see, it has the lowest power consumption, also has the lowest >> performance/watts value. >> At least for kbuild benchmark, powersaving policy has the best >> compromise on powersaving and power efficient. Further more, due to cpu >> boost feature, it has better performance in some scenarios. >> >> powersaving + ondemand userspace + fixed 1.2GHz performance+ondemand >> x = 8 231.318 /75 57 165.063 /166 36 253.552 /63 62 >> x = 16 280.357 /49 72 174.408 /106 54 296.776 /41 82 >> x = 32 325.206 /34 90 178.675 /90 62 314.153 /37 86 >> >> x = 8 233.623 /74 57 164.507 /168 36 254.775 /65 60 >> x = 16 272.54 /38 96 174.364 /106 54 297.731 /42 79 >> x = 32 320.758 /34 91 177.917 /91 61 317.875 /35 89 >> x = 64 326.837 /33 92 179.037 /90 62 320.615 /36 86 > > 17348.850 27400.458 15973.776 > 13737.493 18487.248 12167.816 > 11057.004 16080.750 11623.661 > > 17288.102 27637.176 16560.375 > 10356.52 18482.584 12504.702 > 10905.772 16190.447 11125.625 > 10785.621 16113.330 11542.140 > -- Thanks Alex -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
