RFR(s) #2: 6344935: (spec) clarify specifications for Object.wait overloads

[David Holmes]

On 21/08/2017 2:07 PM, Martin Buchholz wrote:
> On Sun, Aug 20, 2017 at 6:36 PM, David Holmes <david.holmes at oracle.com 
> <mailto:david.holmes at oracle.com>> wrote:
> 
>     On 20/08/2017 6:37 AM, Martin Buchholz wrote:
> 
>         Future projects:
> 
>         377 * <li>The specified amount of real time has elapsed, more or
>         less.
> 
>         Replace with
> 
>         * <li>At least the specified amount of real time has elapsed.
> 
>         (I think I failed to persuade David last time ...)
> 
> 
>     And you will continue to do so. :) In the presence of spurious
>     wakeups it is completely untestable to say "at least the specified
>     time has elapsed"
> 
> 
> My view is that spurious wakeup is a separate item in this list. "The 
> specified amount of real time has elapsed" should only be about "normal" 
> timeout.

And if you could perform whitebox testing that peeks inside to be able 
to make the distinction that would be fine. But in terms of the API and 
any conformance test, it is impossible to distinguish between an "early 
return" and a "spurious return". So specifying "at least ..." is 
meaningless so long as spurious wakeups are allowed.

Cheers,
David

> 377 * <li>The specified amount of real time has elapsed, more or less.
> ...
> 
> 382 * <li>Thread <var>T</var> is awakened spuriously. (See below.)
> 
> I feel that "returning early" should occur only for rare spurious 
> wakeups (and I'd like even those to go away someday).