Paul Bone 08896533f2 Document a bug without fixing it. ...

I've found the cause of a long standing race condition in the parallel
runtime system.  The fix is to properly design the engine state and
notification system in the parallel runtime system.  I've worked on a design
and committed a description.  I've started implementing the changes but found
a new different race condition.  I don't currently have the time to complete
this change, therefore I will commit the documentation of the current
problem and proposed solution.

runtime/mercury_context.c:
    As above, document the current race.

    Also comment on a bug where an idle engine could be notified of a
    context to execute.  This notification could be dropped in some
    situations causing the context to be lost.

runtime/notes/par_engine_state.txt:
runtime/notes/par_engine_state.dot:
    As above, document the proposed new engine state and notification
    design.

2012-09-04 11:42:53 +00:00

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par_engine_state.dot

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par_engine_state.txt

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