[RFC PATCH 0/4] Add support for ARMv8.6 TWED feature

[Jingyi Wang]

Hi Marc,

On 9/29/2020 6:50 PM, Marc Zyngier wrote:
> On 2020-09-29 10:17, Jingyi Wang wrote:
>> TWE Delay is an optional feature in ARMv8.6 Extentions. There is a
>> performance benefit in waiting for a period of time for an event to
>> arrive before taking the trap as it is common that event will arrive
>> “quite soon” after executing the WFE instruction.
> 
> Define "quite soon". Quantify "performance benefits". Which are the
> workloads that actually benefit from this imitation of the x86 PLE?
> 
> I was opposed to this when the spec was drafted, and I still am given
> that there is zero supporting evidence that it bring any gain over
> immediate trapping in an oversubscribed environment (which is the only
> case where it matters).
> 
> Thanks,
> 
>          M.

Sure, I will do more performance tests and post the results as soon as
possible.

Thanks,
Jingyi