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NNTP-Posting-Date: Tue, 10 Jan 2012 09:43:18 -0600
Date: Tue, 10 Jan 2012 07:43:17 -0800
From: Patricia Shanahan <pats@acm.org>
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Subject: Re: Atomic integer array class question
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On 1/10/2012 6:22 AM, raphfrk@gmail.com wrote:
> On Jan 9, 6:56 pm, Patricia Shanahan<p...@acm.org>  wrote:
>> Spin waiting, especially spin waiting that has no delay and includes
>> access to a volatile variable, can be very expensive in terms of load on
>> the processor-memory interconnect.
>
> So, add a Thread.sleep(1); or something ?

I'm not at all sure you basic approach makes sense.

>
>> I'm still unclear what is intent, and what is infrastructure to do with
>> how you are trying to implement the intent. Could you provide a
>> description of what you want to have happen?
>
> It's basically a store that has 3 parts per element
>
> id (short)
> data (short)
> auxData (Object)
>
> However, for most places (say 95%+), it is (0, 0, null), so it really
> only needs only a short.
>
> I am planning to have a short array for the main store.  That will be
> based on AtomicInteger and storing two shorts per index (it uses
> compareAndSet to allow one short out of the int to be updated
> atomically).
...

My premature optimization detector is clicking rapidly. You are still
talking about a particular implementation, not what you want the
implementation to achieve.

Patricia