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From: "Chang S. Bae" <chang.seok.bae@intel.com>
To: linux-kernel@vger.kernel.org, x86@kernel.org, linux-pm@vger.kernel.org
Cc: tglx@linutronix.de, dave.hansen@linux.intel.com,
	peterz@infradead.org, bp@alien8.de, rafael@kernel.org,
	ravi.v.shankar@intel.com, chang.seok.bae@intel.com
Subject: [PATCH v4 0/2] x86/fpu: Make AMX state ready for CPU idle
Date: Tue, 17 May 2022 15:24:28 -0700	[thread overview]
Message-ID: <20220517222430.24524-1-chang.seok.bae@intel.com> (raw)

Hi,

First of all, my apologies for the long delay with my vacation.

Changes from v3 [1]:
* Call out AMX state only needs to be initialized for CPU idle (Thomas).
* Drop the XCR0 accessor changes as not relevant (Dave).

The series is available here:
  git://github.com/intel/amx-linux.git tilerelease

=== Original Cover Letter ===

AMX state is a large state (at least 8KB or more). Entering CPU idle with
this non-initialized large state may result in shallow states while a
deeper low-power state is available.

We can confirm this behavior is implementation-specific. Section 3.3 in [2]
will be updated to clarify this.

Thanks,
Chang

[1]: https://lore.kernel.org/lkml/20220325022219.829-1-chang.seok.bae@intel.com/
[2]: Intel Architecture Instruction Set Extension Programming Reference
     May 2021, https://software.intel.com/content/dam/develop/external/us/en/documents-tps/architecture-instruction-set-extensions-programming-reference.pdf

Chang S. Bae (2):
  x86/fpu: Add a helper to prepare AMX state for low-power CPU idle
  intel_idle: Add a new flag to initialize the AMX state

 arch/x86/include/asm/fpu/api.h       |  2 ++
 arch/x86/include/asm/special_insns.h |  9 +++++++++
 arch/x86/kernel/fpu/core.c           | 13 +++++++++++++
 drivers/idle/intel_idle.c            | 18 ++++++++++++++++--
 4 files changed, 40 insertions(+), 2 deletions(-)


base-commit: 42226c989789d8da4af1de0c31070c96726d990c
-- 
2.17.1


             reply	other threads:[~2022-05-17 22:33 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-17 22:24 Chang S. Bae [this message]
2022-05-17 22:24 ` [PATCH v4 1/2] x86/fpu: Add a helper to prepare AMX state for low-power CPU idle Chang S. Bae
2022-05-18 15:41   ` Dave Hansen
2022-05-18 17:20     ` Chang S. Bae
2022-05-18 17:27       ` Dave Hansen
2022-05-17 22:24 ` [PATCH v4 2/2] intel_idle: Add a new flag to initialize the AMX state Chang S. Bae

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