Re: [PATCH v9 00/10] PMU-EBB support for PPC64 TCG

[Cédric Le Goater]

Hello,

On 12/1/21 16:17, Daniel Henrique Barboza wrote:
> Hi,
>
> In this new version the most significant change is in patch 6,
> where a new hflag allows us to not call the instruction helper
> inside translate.c unless we're absolutely certain that there
> is an instruction count event being sampled and active in the
> PMU. This change turned out to be a big boost in performance
> in the PMU emulation overall, most notably when dealing with
> cycle events that were calling the helper needlessly.
>
> This and all other changes were suggested by David in his review
> of the previous version.


patch 1-8 look good. I still have some questions on the exception
handling and how EBB are gated.

I am asking to get the model right for the next step which should
be to modify the XIVE interrupt controller to generate External
EBB exceptions.

One more comment, not for now, since the EBB patchset is nearly
ready.

May be, it is time to think about introducing a per-CPU model
excp_handlers[] array indexed by POWERPC_EXCP_* exception
numbers and to duplicate some code for the sake of clarity.

Fabiano, isn't it what you had in mind ?

Thanks,

C.