RFR(M): 8154736: enhancement of cmpxchg and copy_to_survivor for ppc64

[Gustavo Romero]

Hi John,

On 04/24/2018 11:42 AM, John Paul Adrian Glaubitz wrote:
> On 04/24/2018 04:20 PM, Doerr, Martin wrote:
>> I think 6% performance gain is really worth doing this change.
> 
> Quick question: Does this pose any assumptions on the instruction set baseline
> on ppc64? I haven't build-tested this yet, but I want to avoid it doesn't break
> on POWER5, for example, which is used in Debian's big-endian ppc64 port.

Yes, it does. But POWER5 and above are ok. Lightweight sync (lwsync) was
introduced with Power ISA v2.03 which, by its turn, maps to POWER5.

Thanks for taking care of Power + Debian :-)


Regards,
Gustavo