From: Dave Hansen <dave.hansen@intel.com>
To: "Chang S. Bae" <chang.seok.bae@intel.com>,
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
Subject: Re: [PATCH v4 1/2] x86/fpu: Add a helper to prepare AMX state for low-power CPU idle
Date: Wed, 18 May 2022 10:27:37 -0700 [thread overview]
Message-ID: <ea52ad4f-0d26-455a-1257-7636f954b002@intel.com> (raw)
In-Reply-To: <d081a3f8-4a66-f411-f1cd-e80d752d3851@intel.com>
On 5/18/22 10:20, Chang S. Bae wrote:
>> That also has a nice side effect that non-AMX systems will get to use a
>> static branch and can also skip over the XGETBV1 entirely.
>
> Yes, but FWIW, as it is non-architectural, the function should be
> consumed only by drivers for AMX systems.
Oh, that's a good point. The new flag is set only on Sapphire Rapids
systems so the new code is only called there as well. I guess it would
only matter if we end up having systems that need this where AMX isn't
universally available, like if it were fused on or off on certain SKUs
(I have no idea if anyone is actually doing this).
next prev parent reply other threads:[~2022-05-18 17:52 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-17 22:24 [PATCH v4 0/2] x86/fpu: Make AMX state ready for CPU idle Chang S. Bae
2022-05-17 22:24 ` [PATCH v4 1/2] x86/fpu: Add a helper to prepare AMX state for low-power " 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 [this message]
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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