path: root/Documentation/scheduler
diff options
authorValentin Schneider <>2020-07-31 20:20:16 +0100
committerIngo Molnar <>2020-08-01 09:19:43 +0200
commit949bcb8135a96a6923e676646bd29cbe69e8350f (patch)
tree42a31dd5c03583cb2bb7e1f120bfe5836f13df5d /Documentation/scheduler
parent65065fd70b5a0f0bbe3f9f1e82c1d38c2db620d0 (diff)
sched/doc: Factorize bits between sched-energy.rst & sched-capacity.rst
Documentation/scheduler/sched-capacity.rst ought to be the canonical place to blabber about SD_ASYM_CPUCAPACITY, so remove its explanation from sched-energy.rst and point to sched-capacity.rst instead. Signed-off-by: Valentin Schneider <> Signed-off-by: Ingo Molnar <> Link:
Diffstat (limited to 'Documentation/scheduler')
1 files changed, 2 insertions, 10 deletions
diff --git a/Documentation/scheduler/sched-energy.rst b/Documentation/scheduler/sched-energy.rst
index 9580c57a52bc..78f850778982 100644
--- a/Documentation/scheduler/sched-energy.rst
+++ b/Documentation/scheduler/sched-energy.rst
@@ -331,16 +331,8 @@ asymmetric CPU topologies for now. This requirement is checked at run-time by
looking for the presence of the SD_ASYM_CPUCAPACITY flag when the scheduling
domains are built.
-The flag is set/cleared automatically by the scheduler topology code whenever
-there are CPUs with different capacities in a root domain. The capacities of
-CPUs are provided by arch-specific code through the arch_scale_cpu_capacity()
-callback. As an example, arm and arm64 share an implementation of this callback
-which uses a combination of CPUFreq data and device-tree bindings to compute the
-capacity of CPUs (see drivers/base/arch_topology.c for more details).
-So, in order to use EAS on your platform your architecture must implement the
-arch_scale_cpu_capacity() callback, and some of the CPUs must have a lower
-capacity than others.
+See Documentation/sched/sched-capacity.rst for requirements to be met for this
+flag to be set in the sched_domain hierarchy.
Please note that EAS is not fundamentally incompatible with SMP, but no
significant savings on SMP platforms have been observed yet. This restriction