Re: [RFC PATCH] perf/amd/ibs: Report physical address for IBS fetch samples

[Ravi Bangoria <ravi.bangoria@amd.com>]

On 18-Aug-26 1:30 PM, Peter Zijlstra wrote:
> On Tue, Aug 18, 2026 at 10:29:08AM +0530, Ravi Bangoria wrote:
>> On 17-Aug-26 1:03 PM, Huang Shijie wrote:
>>> The IBS Fetch sampling does not report the physical address of the
>>> fetched instruction even when PERF_SAMPLE_PHYS_ADDR is requested,
>>> while IBS Op sampling does.
>>>
>>> This patch reports physical address for IBS fetch samples which can be
>>> used for profiling the running program.
>>
>> PERF_SAMPLE_PHYS_ADDR is meant to capture the _data_ physical address, which
>> IBS Fetch doesn't provide. So, repurposing semantics of PERF_SAMPLE_PHYS_ADDR
>> for IBS Fetch seems reasonable.
>>
>> Reviewed-by: Ravi Bangoria <ravi.bangoria@amd.com>
> 
> Well, why confuse things?
> 
> As you say, PHYS_ADDR is for ADDR, which is the *data* address, and
> FETCH is an instruction address, which we find in IP, not DATA.
> 
> What would be the purpose of confusing things and making PHYS_ADDR
> relate to IP?

Agreed, that would create confusion.

Do you think we should introduce a new type PERF_SAMPLE_IP_PHYS_ADDR?
I didn't suggest it earlier because I thought it would be overkill.

Thanks,
Ravi