Re: [PATCH v1 0/3] coresight: Fix for snapshot mode

[Leo Yan]

On Fri, Jun 11, 2021 at 01:31:41AM -0700, Denis Nikitin wrote:
> Hi Suzuki,
> 
> On Thu, Jun 10, 2021 at 9:04 AM Suzuki K Poulose <suzuki.poulose@xxxxxxx> wrote:
> >
> [...]
> >
> > Are you able to confirm if the patch 3 alone fixes the above issue ?
> > I am not convinced that Patch 1 is necessary.
> >
> 
> Yes. "perf cs-etm: Remove callback cs_etm_find_snapshot()" alone fixes
> the issue.

Based on current testing result, we should give high priority for
patches 2 and 3.

The patch 1 is controversial for how to handle the trace data kept
in multiple AUX buffers; essentially it's up to how we understand the
snapshot definition.  I confirmed Intel-PT and CoreSight have the same
behaviour for capturing trace data from multiple AUX ring buffers when
snapshot occurs.

I'd like to leave patch 1/3 out, and resend it if we get conclusion.
At the meantime, @Denis, if you have observed any profiling result
(or profiling quality) difference caused by patch 1, the feedback would
be very valuable.

Thanks a lot for Denis' testing and insight review from Suzuki!

Leo