[Intel-xe] [PATCH v2 03/20] drm/xe: Correlate engine and cpu timestamps with better accuracy

[Rodrigo Vivi]

On Mon, Sep 25, 2023 at 06:37:12PM -0700, Umesh Nerlige Ramappa wrote:
> On Wed, Sep 20, 2023 at 03:29:23PM -0400, Rodrigo Vivi wrote:
> > From: Umesh Nerlige Ramappa <umesh.nerlige.ramappa at intel.com>
> > 
> > Perf measurements rely on CPU and engine timestamps to correlate
> > events of interest across these time domains. Current mechanisms get
> > these timestamps separately and the calculated delta between these
> > timestamps lack enough accuracy.
> > 
> > To improve the accuracy of these time measurements to within a few us,
> > add a query that returns the engine and cpu timestamps captured as
> > close to each other as possible.
> > 
> > Prior work: https://patchwork.freedesktop.org/series/87552/
> > 
> > Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa at intel.com>
> > Signed-off-by: Francois Dugast <francois.dugast at intel.com>
> > Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
> > ---
> 
> Should already have an R-b from Jose based on this -
> https://patchwork.freedesktop.org/patch/552682/?series=122440&rev=1

While incorporating that and fixing IGT, I noticed the inconsistency
present on the v2 that was not part of v1.

Why we have the struct name as engine_cycles now but the query itself
is still cs_cycles? Which one is correct? why do we need both and
cannot align in a single name?

> 
> Thanks,
> Umesh