[concurrency-interest] Propagation ofsignalstonon-interruptedthread

√iktor Ҡlang viktor.klang at gmail.com
Tue Nov 15 14:27:31 EST 2011


On Tue, Nov 15, 2011 at 7:59 PM, Dr Heinz M. Kabutz <
heinz at javaspecialists.eu> wrote:

> **
> On an only vaguely related note, I discovered today, whilst doing a
> throughput test of atomic integer vs reentrant lock, that every time you
> call lock.lock(), it creates a new object of 32 bytes!  For some reason, I
> always assumed that lock.lock() would not construct any objects, so was
> surprised when the GC started acting up.  The object that is constructed is
> the AbstractQueuedSynchronizer$Node in the addWaiter() method in the
> AbstractQueuedSynchronizer.
>

Yeah, that one's a real treat.


>
> Regards
>
> Heinz
> --
> Dr Heinz M. Kabutz (PhD CompSci)
> Author of "The Java(tm) Specialists' Newsletter"
> Sun Java Champion
> IEEE Certified Software Development Professionalhttp://www.javaspecialists.eu
> Tel: +30 69 72 850 460
> Skype: kabutz
>
>
>
> On 11/15/11 4:57 PM, Martin Buchholz wrote:
>
>
>
> On Mon, Nov 14, 2011 at 18:37, David Holmes <davidcholmes at aapt.net.au>wrote:
>
>>  One example of some broken code is not very compelling. This code
>> doesn't even handle timeout correctly. I strongly suspect the author of
>> this code was not relying on no-spurious-wakeups but was simply completely
>> ignorant of them and so would have used the same style of code even with
>> Object.wait.
>>
>
>  Sure.
>
>  My argument is not about careful programmers who have thoughtfully read
> the spec, whose number is vanishingly small.  This is all about real-world
> crappy code in production that happens to work today, and will fail
> unpredictably under stress if you withdraw the de-facto guarantees.
>
>  If Object.wait has also been providing the de-facto guarantee in recent
> releases, I would like its spec updated as well to provide the stronger
> guarantee.  But my argument is stronger for j.u.c.locks, since everyone
> uses the same implementation in practice.
>
>  Martin
>
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-- 
Viktor Klang

Akka Tech Lead
Typesafe <http://www.typesafe.com/> - Enterprise-Grade Scala from the
Experts

Twitter: @viktorklang
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