Re: JavaMemoryModel: Dropping coherence is more complicated than we thought

From: Doug Lea (dl@altair.cs.oswego.edu)
Date: Tue Nov 09 1999 - 19:35:19 EST


Back to:

  int v;
  int getValue() {
    if (v == 0)
      v = computeValue();
    return v;
  }

Is getValue allowed by LC to return zero even in some purely single threaded
context? The possibility of mirrored memory worlds ...

> An example of architecture (Dr. Amaral from CAPSL had this idea) where
> the example above could have V(r3)!=0 and V(r4)==0 both true would
> provide more than one main memory. A system with several mirrors for its
> main memory, where r3 would get w2 from one mirror and r4 would get w0
> from another.

... has me both confused and worried.

-Doug

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