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

[Umesh Nerlige Ramappa]

On Tue, Sep 26, 2023 at 02:48:13PM -0400, Rodrigo Vivi wrote:
>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?

Jose had commented that XE does not have the concept of CS and asked for 
a rename to engine. In the latest revision of this series, I had 
replaces cs with engine everywhere.

We should use engine.

Latest series - https://patchwork.freedesktop.org/series/122440/

Thanks,
Umesh
>
>>
>> Thanks,
>> Umesh