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Diffstat (limited to 'Documentation/admin-guide/pm/intel_pstate.rst')
| -rw-r--r-- | Documentation/admin-guide/pm/intel_pstate.rst | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/Documentation/admin-guide/pm/intel_pstate.rst b/Documentation/admin-guide/pm/intel_pstate.rst index 26e702c7016e..66287f8d645f 100644 --- a/Documentation/admin-guide/pm/intel_pstate.rst +++ b/Documentation/admin-guide/pm/intel_pstate.rst @@ -348,11 +348,12 @@ HyperThreading (HT) in the context of Intel processors, is enabled on at least one core, ``intel_pstate`` assigns performance-based priorities to CPUs. Namely, the priority of a given CPU reflects its highest HWP performance level which causes the CPU scheduler to generally prefer more performant CPUs, so the less -performant CPUs are used when the other ones are fully loaded. However, SMT -siblings (that is, logical CPUs sharing one physical core) are treated in a -special way such that if one of them is in use, the effective priority of the -other ones is lowered below the priorities of the CPUs located in the other -physical cores. +performant CPUs are used when the other ones are fully loaded. SMT siblings +(that is, logical CPUs sharing one physical core) are given the same priority. +The scheduler can pull tasks from lower-priority cores and place them on any +sibling. Since the scheduler spreads tasks among physical cores, tasks will be +placed on the SMT siblings of physical cores only after all physical cores are +busy. This approach maximizes performance in the majority of cases, but unfortunately it also leads to excessive energy usage in some important scenarios, like video |