[Intel-gfx] [PATCH v2] drm/i915/execlists: Track begin/end of execlists submission sequences

[Chris Wilson]

Quoting Francisco Jerez (2018-04-02 17:32:20)
> Chris Wilson <chris at chris-wilson.co.uk> writes:
> 
> > We would like to start doing some bookkeeping at the beginning, between
> > contexts and at the end of execlists submission. We already mark the
> > beginning and end using EXECLISTS_ACTIVE_USER, to provide an indication
> > when the HW is idle. This give us a pair of sequence points we can then
> > expand on for further bookkeeping.
> >
> > v2: Refactor guc submission to share the same begin/end.
> >
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
> > Cc: Francisco Jerez <currojerez at riseup.net>
> > Reviewed-by: Francisco Jerez <currojerez at riseup.net> #v1
> 
> Thanks, v2 is also:
> 
> Reviewed-by: Francisco Jerez <currojerez at riseup.net>

Pushed this as it should give us a common hook for the two series.

I belatedly remembered, that we do have a similar begin/end sequence
markers for *user* activity, mark_busy, mark_idle. These are signaled on
receipt of the first request from the user (may be an arbitrary time
before execution) and after completion of the final request, plus some
hysteresis of 100ms to 2s. It's not as exact as tracking activity on
execlists, but it would be nice if you could balance the pros/cons when
hooking up. That knowledge will be helpful for directing future api
changes, e.g. no one has done a thorough investigation of how far we can
push S0ix afaik.
-Chris