[concurrency-interest] Java Memory Model versus dotnet Memory
jmanson at cs.purdue.edu
Thu Nov 3 11:57:23 EST 2005
Osvaldo Pinali Doederlein wrote:
> This excellent post (from Microsoft's JIT program manager) is a very
> good overview of this issue:
> Go straight to "CAVEATS for V1" in the end. Basically, it seems that
> Microsoft gets away with a weak MM and implementation, because they
> support mostly the P5/P6 platform which hardware MM is very strong.
> So they can use all compiler optimizations they want without issues.
> But IIRC the Intanium is not as nice as the Pentium, so I'd expect
> MS to have improved this in .NET 2.0 which supports 64-bit platforms.
I'm not sure how excellent this article is. For example, his LazyInit
example ignores reordering by the reader. Even with the rules he
states, you would really need a memory barrier before the first read of
Having said that, the post is 3 years old and describes the ECMA
standard, which we know they are ignoring. So it may not be all that
useful in understanding what they are doing now.
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