Re: [PATCH 10/10] perf hisi-ptt: Add decoder version compatibility

On 2026/7/14 1:49, Bjorn Helgaas wrote:
> On Thu, Jun 04, 2026 at 03:50:05PM +0800, Sizhe Liu wrote:
>> The hisi_ptt packet decoder now performs detailed field-level parsing
>> of TLP header DW2 and DW3 based on the message type classified from
>> DW0 (added in the previous patches). However, trace data recorded
>> with older versions of the tool does not contain the information
>> needed for this detailed parsing, and should continue to use the
>> generic field-name-only output.
> Add blank line between paragraphs.  Also applies to 05/10.
>
>> Introduce a version field (V1/V2) in the auxtrace info record to
>> distinguish between the two data formats:
> IMO a blank line here would also improve readability.  And consider
> indenting bullet points a couple spaces.  Also applies to other commit
> logs in this series, including sample formats.
>
>> - V1 (legacy): auxtrace priv contains only PMU type. DW2 and DW3
>>    are printed with generic field names only, no message-type-based
>>    field decoding.
>> - V2 (current): auxtrace priv contains PMU type and version. DW2
>>    and DW3 are decoded according to the TLP message type (MWr, Msg,
>>    Atomic, IO, CPL, Cfg) with detailed field names.
> Could use imperative mood, e.g.,
>
>    - V1 (legacy): auxtrace priv contains only PMU type. Print DW2 and
>      DW3 generic field names only, no message-type-based field
>      decoding.
>
>    - V2 (current): auxtrace priv contains PMU type and version. Decode
>      DW2 and DW3 according to the TLP message type (MWr, Msg, Atomic,
>      IO, CPL, Cfg) with detailed field names.
Thanks, all the preceding suggestions will be modified in v2.
>> At recording time, set the version to HISI_PTT_DECODER_V2 in the
>> auxtrace info. At decoding time, determine the version from the
>> priv data size and the version field:
>> - If priv_size >= V2, read the version from priv[1].
>> - If priv_size < V2, assume V1 for backward compatibility.
>> - If version is unknown (future), warn and decode auxtrace as v2.
>>
>> Also add the version to the dump output alongside the PMU type.
>> Adjust hisi_ptt_pkt_size position to adapt to compilation.
> AFAICS this series adds new functionality and probably doesn't qualify
> for "stable" tags, given the documented rules.  But I think the
> maintainers are pretty aggressive about backporting things anyway.
Hi Bjorn,
Thanks for your response and for clarifying the policy regarding the 
stable tag.
You're right, patches 03-10 in this series are new functionality and 
shouldwait
for the next merge window.

For patch 01 and patch 02, they do fix the issue of inaccurate packet 
parsing,
I think it is better to separate them from the patch series.
I am sending them individually after fixing the C bitfields issues if 
that makes things clearer.

If you have any suggestions on this split, please feel free to let me know.

Regards,
Sizhe