Re: RFD: Should we remove the HLT check? (was Re: [PATCH 1/8] x86: avoid check hlt if no timer interrupts)

H. Peter Anvin
2010-05-07T20:38:04Z

On 05/07/2010 01:33 PM, Arjan van de Ven wrote:
> On 5/7/2010 13:32, H. Peter Anvin wrote:
>>
>> I really wish I knew the exact systems affected by the HLT bug. If I
>> remember correctly, it was some 386 systems -- or possibly 486 systems
>> as well -- a very long time ago. This test just provides a diagnosis if
>> the system really is bad (it hangs with an obvious message) at the cost
>> of some 40 ms to the system boot time. I suspect C1 (HLT) being broken
>> is not anywhere close to the predominant power management problem in the
>> current day, and as such I'm wondering if this particular test hasn't
>> outlived its usefulness.
>>
>> Thoughts?
>
> we could at least hide it behind the "don't run on pentium or newer" config options..

I'd be cool skipping it for family 5 or newer. I'm just wondering if we
should kill it completely -- IIRC it was only a handful of 386/486
systems which had problems, usually due to marginal power supplies which
couldn't handle the noise of a variable load (DOS not having any power
management would run at a reliable 100% load) -- that's not exactly the
type of systems which would have survived to modern day.

-hpa