path: root/Documentation/scheduler
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authorLukasz Luba <>2020-11-03 09:05:58 +0000
committerRafael J. Wysocki <>2020-11-10 20:29:28 +0100
commit5a64f775691647c242aa40d34f3512e7b179a921 (patch)
tree469e6eeb2e64d129f0b2242084875081e65ef4ab /Documentation/scheduler
parentc250d50fe2ce627ca9805d9c8ac11cbbf922a4a6 (diff)
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 <>
Diffstat (limited to 'Documentation/scheduler')
1 files changed, 5 insertions, 0 deletions
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