Re: [PATCH 1/10] Cr4 is valid on some 486s

[Andi Kleen]

Dave Jones <davej@xxxxxxxxxx> writes:
> 
> Looks like the Ubuntu people already did this...
> 
> http://www.kernel.org/git/?p=linux/kernel/git/bcollins/ubuntu-2.6.git;a=commitdiff;h=048985336e32efe665cddd348e92e4a4a5351415;hp=1cb630c2b5aaad7cedaa78aa135e6cecf5ab91ac

It's probably not needed. At least AMD K7/K8 has a SYSCFG MSR bit to
do this (or rather they disable bus cycles for locks that makes them
very cheap) Intel has one too in a different MSR that looks similar.
With some luck they're even already set by the BIOS on UP systems.  I
know they are on some AMD systems.

But overall the feature doesn't help longer term because single
threaded CPUs are on their way out.

-Andi
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