Messages in this thread | | | From | Andi Kleen <> | Subject | Re: Synchronizing Bit operations V2 | Date | Fri, 31 Mar 2006 18:37:33 +0200 |
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On Friday 31 March 2006 18:22, Hans Boehm wrote:
> My impression is that approach (1) tends not to stick, since it involves > a substantial performance hit on architectures on which the fence is > not implicitly included in atomic operations. Those include Itanium and > PowerPC.
At least the PPC people are eating the overhead because back when they didn't they had a long string of subtle powerpc only bugs caused by that
It's a stability/maintainability vs performance issue. I doubt the performance advantage would be worth the additional work. I guess with the engineering time you would need to spend getting all this right you could do much more fruitful optimizations.
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