Michael Schnell schrieb:
On 06/27/2011 04:58 PM, Andrew Brunner wrote:
You're totally underestimating the need for a memory barrier :
While I do know that memory barriers are the way to go to avoid the
expensive use of Mutex and friends, I am positive that an MB is not
necessary if all accesses to something are protected by a Mutex
You forget the strength of protection. A MB will disallow immediately
any concurrent access to the memory area - no way around. Protection by
other means only can work in *perfect* cooperation, a very weak model.
Furthermore a MB still requires management by other means (MUTEX...), to
prevent deadlocks. Unless the MB will block *any* activity on *all* the
critical program data at once, what would lead to single-thread
behaviour of the program.
DoDi
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