Re: [PATCH v1 00/11] perf script: Refactor branch flags for Arm SPE

[Leo Yan]

Hi Ian, Namhyung,

On Wed, Feb 12, 2025 at 09:29:28PM -0800, Namhyung Kim wrote:

[...]

> > > > Built and tested (on x86). A little strange patch 5 adds a new bit not
> > > > at the end, but "Sample parsing" test wasn't broken so looks like it
> > > > is good. I was surprised the use of value in the union:
> > > > ```
> > > > struct branch_flags {
> > > > union {
> > > > u64 value;
> > > > struct {
> > > > u64 mispred:1;
> > > > u64 predicted:1;
> > > > ...
> > > > ```
> > > > didn't get broken. Perhaps there's an opportunity for additional tests.
> 
> Probably because it just checks the value as a whole u64, not each
> bitfield.  But it seems to test if the value of the input sample data
> and synthesized-and-parsed output sample data is same.  So it may not be
> important what value it has.
> 
> Anyway it'd be nice if any ARM folks can review this series.

After discussed with James, I concluded that it has risk to break
other arches (e.g., x86 LBR).  So I have sent out patch set v2 [1]
to keep the existed bitfield layout in patch 05, and added Ian's
review tags.

I expect James will give a review the new series.

Thanks,
Leo

[1] https://lore.kernel.org/linux-perf-users/20250214111936.15168-1-leo.yan@xxxxxxx/T/#t