Re: [PATCH RFC] x86: avoid atomic operation in test_and_set_bit_lock if possible

Borislav Petkov
2011-03-25T10:51:23Z

On Fri, Mar 25, 2011 at 05:59:31AM -0400, Ingo Molnar wrote:
> > [...] but you probably need to make a full pass to make sure we dont have a
> > MSR failure -this should return false in this case.
>
> Wanted to keep this patch simple - we are not really hitting MSR
> failure cases in practice, and by getting the message the user is at
> least warned that *something* is amiss.

AFAIR, Robert was telling me couple of months ago about some braindead
BIOSes doing power management by using at least one perf counter. A
radical approach like that might interfere with that BIOS since it will
try to reprogram the counter continuously and f*ck up OS PMU use.

Anyway, adding Robert for clarification.

--
Regards/Gruss,
Boris.

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