[Skiboot] [RFC PATCH] core/opal: Add OPAL call statistics

[Cédric Le Goater]

On 2/29/20 10:27 AM, Nicholas Piggin wrote:
> Cédric Le Goater's on February 29, 2020 4:34 am:
>> Here is a proposal to collect OPAL call statistics, counts and duration,
>> and track areas we could possibly improve.
>>
>> With a small Linux driver to dump the stats in debugfs, here is what
>> we get on a P9 after boot:
> 
> Seems interesting... you could just do it all on the Linux side though.

I thought we might collect more data from OPAL in opal_exit. 

> Any reason you want these stats? 

HW configuration (XIVE) is in mind but it could be applied to other 
areas.

1. To see which calls are being used and how frequently 
2. to track average and max values which would reflect issues in 
   OPAL, locking or polling.
3. to see impact of some changes

> I'd like to try get basic perf and possibly even ftrace support for 
> OPAL (driven from Linux). It's still a way off but coming along slowly.

Nice. 

Thanks,

C.