[PATCH][SRU][OEM-5.14] Improve performance and idle power consumption for AMD CPUs

Alex Hung alex.hung at canonical.com
Sat Oct 9 02:07:34 UTC 2021

  BugLink: https://bugs.launchpad.net/bugs/1941893


  This can improve AMD performance for all Zen or newer CPU which support C3 shares cache.

  Its not necessary to flush the caches in software before entering C3.

  Empirical measurements show:
   40-45% improvement in speedometer score.
   ~15% improvement in idle power.

  The patch is in linux-next (tag next-20211007) and can be found @ https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/arch/x86/kernel/acpi/cstate.c?id=a8fb40966f19ff81520d9ccf8f7e2b95201368b8


  This is requested by AMD.

[Where problems could occur]

  Low risk. This only works on AMD Zen CPUs that supports this features. AMD
  tested it and provided estimated measurement results.

Deepak Sharma (1):
  x86: ACPI: cstate: Optimize C3 entry on AMD CPUs

 arch/x86/kernel/acpi/cstate.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)


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