RE: JavaMemoryModel: Performing speculative writes ahead of loops that may not terminate

From: Eliot Moss (
Date: Sun May 30 2004 - 20:01:40 EDT

>>>>> "Sylvia" == Sylvia Else <> writes:

    Sylvia> At 09:36 PM 30/05/2004 +1000, David Holmes wrote:
>> Master thread fills in a buffer with work items and then starts a new worker
>> thread to process the buffer. Worker threads executes:
>> while (!buf.empty()) process(buf.take());
>> workerFinished = true;
>> where workerFinished is a volatile. Not quite as dramatic as firing the
>> missiles, but same basic problem.

    Sylvia> All the actions performed by the loop happen-before the setting of
    Sylvia> workerFinished to true. Any thread that reads true from workerFinished must
    Sylvia> see the effects of all the actions that happen-before it, which includes
    Sylvia> the processing of the work in the buffer.

    Sylvia> I don't see the problem.

I would agree. The interesting case in this context is where the loop does
only thread-private work, perhaps only on local variables all of which have
been allocated to registers .... EM
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