[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 03:07:20PM -0400, Rodrigo Vivi wrote:
>On Tue, Sep 26, 2023 at 11:58:58AM -0700, Umesh Nerlige Ramappa wrote:
>> 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/
>
>yeap, I got from there...
>I still see
>+#define DRM_XE_QUERY_CS_CYCLES		6
>there
>;)
>
>I can do the renaming locally if this is the right thing to do...

oh, I think I missed that. It should be changed to 
DRM_XE_QUERY_ENGINE_CYCLES.

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