Hi Suravee!

On 15/04/2021 10:28, Suthikulpanit, Suravee wrote:
> David,
> 
> On 4/14/2021 10:33 PM, David Coe wrote:
>> Hi Suravee!
>>
>> I've re-run your revert+update patch on Ubuntu's latest kernel 
>> 5.11.0-14 partly to check my mailer's 'mangling' hadn't also reached 
>> the code!
>>
>> There are 3 sets of results in the attachment, all for the Ryzen 
>> 2400G. The as-distributed kernel already incorporates your IOMMU RFCv3 
>> patch.
>>
>> A. As-distributed kernel (cold boot)
>>     >5 retries, so no IOMMU read/write capability, no amd_iommu events.
>>
>> B. As-distributed kernel (warm boot)
>>     <5 retries, amd_iommu running stats show large numbers as before.
>>
>> C. Revert+Update kernel
>>     amd_iommu events listed and also show large hit/miss numbers.
>>
>> In due course, I'll load the new (revert+update) kernel on the 4700G 
>> but won't overload your mail-box unless something unusual turns up.
>>
>> Best regards,
>>
> 
> For the Ryzen 2400G, could you please try with:
> - 1 event at a time
> - Not more than 8 events (On your system, it has 2 banks x 4 counters/bank.
> I am trying to see if this issue might be related to the counters 
> multiplexing).
> 
> Thanks,

Herewith similar one-at-a-time perf stat results for the Ryzen 4700U. As 
before, more than 8 events displays the third (%) column and (sometimes) 
'silly' numbers in the first column.

-- 
David