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Subject[PATCH 0/3] Add support for frequency invariance to AMD EPYC Zen2
Date
This series adds support for frequency invariant accounting on AMD EPYC Zen2
(aka "Rome"). The first patch by Nathan lays out the foundation by querying
ACPI infrastructure for the max boost frequency of the system. Specifically,
this value is available via the CPPC machinery; the previous EPYC generation,
namely Zen aka "Naples", doesn't implement that and frequency invariance won't
be supported.

The second patch sets the estimate for freq_max to be the midpoint between
max_boost and max_P, as that works slightly better in practice.

A side effect of this series is to provide, with the invariant schedutil
governor, a suitable baseline to evaluate a (still work-in-progress)
CPPC-based cpufreq driver for the AMD platform (see
https://lore.kernel.org/lkml/cover.1562781484.git.Janakarajan.Natarajan@amd.com
if/when it will resubmitted.

Giovanni Gherdovich (2):
x86, sched: Use midpoint of max_boost and max_P for frequency
invariance on AMD EPYC
x86: Print ratio freq_max/freq_base used in frequency invariance
calculations

Nathan Fontenot (1):
x86, sched: Calculate frequency invariance for AMD systems

arch/x86/include/asm/topology.h | 8 ++++
arch/x86/kernel/smpboot.c | 79 +++++++++++++++++++++++++++++----
drivers/acpi/cppc_acpi.c | 5 +++
3 files changed, 84 insertions(+), 8 deletions(-)

--
2.26.2

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