Subj : Re: [.NET] Volatile Fields [correction]
To   : comp.programming.threads
From : Joe Seigh
Date : Thu Sep 22 2005 07:26 pm

David Hopwood wrote:
> Joe Seigh wrote:
>>Lousy performance compared to what?
> 
> 
> Now that I look at your suggestion more closely, it doesn't appear to work,
> so its performance is moot.
> 
> Start with F (fence) == Y == Z == 0.
> 
> P1:  F = 1; Y = 1;
> P2:  if (Y == 1) { (void) F; F = 1; Z = 1; }
> P3:  if (Z == 1) { (void) F; assert(Y == 1); }
> 
> can fail, e.g. in this execution:
> 
It's a store/store or release memory barrier so it has to be after the
stores that you want to be made visible.  PC type 2 has global visibility
guarantees so you don't need it for that.

-- 
Joe Seigh

When you get lemons, you make lemonade.
When you get hardware, you make software.

.