[concurrency-interest] Concurrency-interest Digest, Vol 52, Issue 1

Hans Boehm Hans.Boehm at hp.com
Tue May 12 11:38:48 EDT 2009



On Tue, 12 May 2009, Brian Goetz wrote:

> Or, to simplify further: volatile reads cheap, volatile writes expensive.
>

Yes, provided you remember that that's X86-specific.  At least for C++
atomics, I believe IBM finally decided on an implementation strategy
for PowerPC that makes writes cheaper.  Java volatiles are equivalent
in this respect, so I would expect the same.  For ARM, they both require
the same, relatively cheap, I'm told, fence.  Itanium is similar to X86
in this respect.

Hans



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