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

[Sizhe Liu]

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