JavaMemoryModel: Pentium memory model

From: Bill Pugh (pugh@cs.umd.edu)
Date: Sun Jan 16 2000 - 22:26:56 EST


Does anybody know, with any confidence, what memory model is provided
by Pentium processors?

Here is what I've heard, but not with confidence:

   * The Pentium implements a TSO memory model; writes can be reordered with
     following reads, but no other reorders are possible.

   * The Pentium doesn't offer a memory barrier instruction. The only
instruction
     that has the effect of a memory barrier is the processor ID instruction,
     which looks like it might be expensive.

Does anyone have any better information?

        Bill Pugh
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