Qais Yousef 99b704ae7a sched/fair: Detect capacity inversion
commit 44c7b80bffc3a657a36857098d5d9c49d94e652b upstream.

Check each performance domain to see if thermal pressure is causing its
capacity to be lower than another performance domain.

We assume that each performance domain has CPUs with the same
capacities, which is similar to an assumption made in energy_model.c

We also assume that thermal pressure impacts all CPUs in a performance
domain equally.

If there're multiple performance domains with the same capacity_orig, we
will trigger a capacity inversion if the domain is under thermal
pressure.

The new cpu_in_capacity_inversion() should help users to know when
information about capacity_orig are not reliable and can opt in to use
the inverted capacity as the 'actual' capacity_orig.

Signed-off-by: Qais Yousef <qais.yousef@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220804143609.515789-9-qais.yousef@arm.com
(cherry picked from commit 44c7b80bffc3a657a36857098d5d9c49d94e652b)
[fix trivial conflict in kernel/sched/sched.h due to code shuffling]
Signed-off-by: Qais Yousef (Google) <qyousef@layalina.io>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-26 13:51:53 +02:00
2023-02-25 12:06:45 +01:00
2023-03-17 08:49:04 +01:00
2021-10-18 20:22:03 -10:00
2023-04-20 12:13:57 +02:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
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In order to build the documentation, use ``make htmldocs`` or
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    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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