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What is going on when Joulemeter runs with logical cores? RRS feed

  • Question

  • I've been running tests with Joulemeter and a compute-intensive threaded application. When I run in serial, I get a measure of CPU usage. When I run with two threads on my dual core processor that number doubles, which is to be expected. If I have Hyper-Threading Technology (HT) turned on and run the application with four threads (using the 4 logical cores) the serial power consumption number is quadrupled. (When I run 8 threads on 4 logical cores, I get no increase in power usage.)

    I'm sure there is some added energy consumption by running extra threads in logical cores, but is it really the same as running on a single physical core? (I hope not.) Is there some way to remove this bias in the tool?

    --clay

    Friday, February 10, 2012 5:16 PM