Re: The code example in onSpinWait() Javadoc

On Mon, Nov 18, 2019 at 4:37 AM Andrew Haley via Concurrency-interest
<[email protected]> wrote:
>
> On 11/17/19 11:46 PM, Doug Lea via Concurrency-interest wrote:
>
> > Usage may interact with GC, reference handling, and safepoints: in
> > some contexts "a short while" isn't usually short, but we don't have
> > a way of portably discussing such issues in javadocs. It's also one
> > of the reasons we don't include a spinlock utility -- we cannot
> > easily guess how best to write one that works well across enough
> > usage contexts. (But we do make it easy to write them via tryLock.)
>
> Sure, these ideas are hard to express if we restrict ourselves to
> the mythical "write once, run anywhere" Java, but by the time we're
> talking about writing our own spinlocks we're a long way from that.
>
> "Everybody" ;-) knows that you should only spin for about (half?) the
> same time as a simple system call, and that this is about 1000
> iterations of a trivial loop. Intuitively this makes sense: you don't
> want to make an (expensive) system call rather than just waiting for a
> little while.

Should we not express this sentiment in the documentation somehow even
if it is not perfectly applicable to every operating environment,
since it's clearly not widely understood?

-- 
- DML

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