[ltt-dev] [URCU PATCH] atomic: provide seq_cst semantics on powerpc

[Mathieu Desnoyers]

* Paolo Bonzini (pbonzini at redhat.com) wrote:
> On 09/22/2011 02:27 AM, Mathieu Desnoyers wrote:
>> Paolo: if you are interested in optimising powerpc uatomic ops further,
>> add, sub, inc, dec, "or", "and", basically anything that is not
>> xchg/add_return/cmpxchg could use versions of the cmpxchg that does not
>> have the lwsync/sync barriers.
>
> Or they could just be rewritten in assembly with a manual ll/sc loop.

Sure, although I suspect the output assembly would be pretty much the
same if we share a common barrier-less permeable cmpxchg for all those
primitives on powerpc on modern compilers vs hand-coding each primitive.
I might be wrong though.

Thanks,

Mathieu

>
> Paolo
>

-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com