[cpp-threads] Update

[Peter Dimov]

Boehm, Hans wrote:
>> From: Peter Dimov
>> Sent: Monday, July 10, 2006 2:21 PM
>> To: C++ threads standardisation
>> Subject: Re: [cpp-threads] Update
>>
>> Boehm, Hans wrote:
>>
>>>> This formulation supercedes both strong CAS and weak CAS, as it's
>>>> allowed to fail. A strong CAS is easily built on top of it
>> by using a
>>>> retry loop.
>>
>>> You're assuming the feature test for whether this is wait-free will
>>> yield false if it can fail spuriously?  Otherwise you can't build
>>> guaranteed wait-free algorithms?  Or do you not care?  (This is a
>>> serious question:  I'm not sure if I do.)
>>
>> I can't think of a reason to ever use that feature test. What
>> could I do with the answer?
>
> Presumably fail conspicuously with a message that you can't meet a
> hard real-time guarantee?

That (fail with an error message) was the best I could come up with, too. 
It's not a particularly important use case in my opinion.

As for the hard real-time guarantee, how would you meet that with a CAS that 
doesn't fail spuriously? Non-spurious failures can also make the code miss 
the deadline.

(Spuriously == because of false sharing?)