Bug#464962: Do AMD K7 family CPUs support long noops?

To: "H. Peter Anvin" <hpa@zytor.com>
Cc: 464962@bugs.debian.org
Subject: Bug#464962: Do AMD K7 family CPUs support long noops?
From: Graham <graham.knap@gmail.com>
Date: Wed, 13 Feb 2008 16:43:52 -0500
Message-id: <[🔎] 6ce96e330802131343n56e95854m74e7b7821b054c0f@mail.gmail.com>
Reply-to: Graham <graham.knap@gmail.com>, 464962@bugs.debian.org

Hello,

I am wondering whether anyone has looked into which AMD CPUs support
these instructions. I would think that installing a 486 kernel on an
AthlonXP, for example, would be quite sub-optimal.

i.e. can you safely enable X86_P6_NOP for other CPUs, such as AMD
K7/K8, VIA C3/C7, or Efficeon? If not, would it be more sensible to
avoid using these instructions?

It appears that at least some VIA C3 CPUs do not support these opcodes:

http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=463606#45

-- graham

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