From 5a64f775691647c242aa40d34f3512e7b179a921 Mon Sep 17 00:00:00 2001 From: Lukasz Luba Date: Tue, 3 Nov 2020 09:05:58 +0000 Subject: PM: EM: Clarify abstract scale usage for power values in Energy Model The Energy Model (EM) can store power values in milli-Watts or in abstract scale. This might cause issues in the subsystems which use the EM for estimating the device power, such as: - mixing of different scales in a subsystem which uses multiple (cooling) devices (e.g. thermal Intelligent Power Allocation (IPA)) - assuming that energy [milli-Joules] can be derived from the EM power values which might not be possible since the power scale doesn't have to be in milli-Watts To avoid misconfiguration add the requisite documentation to the EM and related subsystems: EAS and IPA. Signed-off-by: Lukasz Luba Signed-off-by: Rafael J. Wysocki --- Documentation/scheduler/sched-energy.rst | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'Documentation/scheduler') diff --git a/Documentation/scheduler/sched-energy.rst b/Documentation/scheduler/sched-energy.rst index 001e09c95e1d..afe02d394402 100644 --- a/Documentation/scheduler/sched-energy.rst +++ b/Documentation/scheduler/sched-energy.rst @@ -350,6 +350,11 @@ independent EM framework in Documentation/power/energy-model.rst. Please also note that the scheduling domains need to be re-built after the EM has been registered in order to start EAS. +EAS uses the EM to make a forecasting decision on energy usage and thus it is +more focused on the difference when checking possible options for task +placement. For EAS it doesn't matter whether the EM power values are expressed +in milli-Watts or in an 'abstract scale'. + 6.3 - Energy Model complexity ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ -- cgit v1.2.3-59-g8ed1b