[PATCH 0/2] Some improvements to the cpuidle menu governor
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From: Arjan van de Ven on 9 May 2010 19:10 Hi, two patches to the menu governor that, together, boost the quality of the decisions it makes significantly (results below). The first patch is basically a bugfix, while the second patch adds some smarts to the algorithm. Both patches only impact the idle-duration predictor (for those unfamiliar with the menu governor, the menu governor first tries to predict the idle duration, and then uses a set of heuristics to pick a suitable idle state based on this prediction. The better the prediction the better the decision ends up being) To show the quality of the predictor, I added some instrumentation where I had perf report out the result of the current, after patch 1 and after patch 2 prediction value as well as the actual idle duration as measured at the end of the idle period. The test run I give below had 69854 samples (other runs had pretty much the same result). The quality indicator I use is the percentage of samples for which the prediction is within a certain factor of the actual duration. Factor before patches patch 1 patch 1+2 1.5x 29.1% 30.4% 34.1% 2x 33.6% 49.3% 52.9% 4x 43.6% 73.6% 75.2% 10x 56.9% 86.1% 86.5% 100x 78.4% 97.0% 97.2% -- Arjan van de Ven Intel Open Source Technology Centre For development, discussion and tips for power savings, visit http://www.lesswatts.org -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |