[Intel-gfx] [PATCH 3/3] drm/i915: Include the HW breadcrumb whenever we trace the global_seqno

[Chris Wilson]

Quoting Tvrtko Ursulin (2018-03-29 09:42:52)
> 
> On 27/03/2018 22:01, Chris Wilson wrote:
> > When we include a request's global_seqno in a GEM_TRACE it often helps
> > to know how that relates to the current breadcrumb as seen by the
> > hardware.
> > 
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > ---
> >   drivers/gpu/drm/i915/i915_request.c | 28 +++++++++++++++++-----------
> >   drivers/gpu/drm/i915/intel_lrc.c    |  6 ++++--
> >   2 files changed, 21 insertions(+), 13 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
> > index 2314a26cd7f8..585242831974 100644
> > --- a/drivers/gpu/drm/i915/i915_request.c
> > +++ b/drivers/gpu/drm/i915/i915_request.c
> > @@ -214,8 +214,11 @@ static int reset_all_global_seqno(struct drm_i915_private *i915, u32 seqno)
> >               struct i915_gem_timeline *timeline;
> >               struct intel_timeline *tl = engine->timeline;
> >   
> > -             GEM_TRACE("%s seqno %d -> %d\n",
> > -                       engine->name, tl->seqno, seqno);
> > +             GEM_TRACE("%s seqno %d (current %d) -> %d\n",
> > +                       engine->name,
> > +                       tl->seqno,
> > +                       intel_engine_get_seqno(engine),
> > +                       seqno);
> >   
> >               if (!i915_seqno_passed(seqno, tl->seqno)) {
> >                       /* Flush any waiters before we reuse the seqno */
> > @@ -386,10 +389,11 @@ static void i915_request_retire(struct i915_request *request)
> >       struct intel_engine_cs *engine = request->engine;
> >       struct i915_gem_active *active, *next;
> >   
> > -     GEM_TRACE("%s(%d) fence %llx:%d, global_seqno %d\n",
> > -               engine->name, intel_engine_get_seqno(engine),
> > +     GEM_TRACE("%s fence %llx:%d, global_seqno %d, current %d\n",
> > +               engine->name,
> >                 request->fence.context, request->fence.seqno,
> > -               request->global_seqno);
> > +               request->global_seqno,
> > +               intel_engine_get_seqno(engine));
> >   
> >       lockdep_assert_held(&request->i915->drm.struct_mutex);
> >       GEM_BUG_ON(!i915_sw_fence_signaled(&request->submit));
> > @@ -508,10 +512,11 @@ void __i915_request_submit(struct i915_request *request)
> >       struct intel_engine_cs *engine = request->engine;
> >       u32 seqno;
> >   
> > -     GEM_TRACE("%s fence %llx:%d -> global_seqno %d\n",
> > -               request->engine->name,
> > +     GEM_TRACE("%s fence %llx:%d -> global_seqno %d, current %d\n",
> > +               engine->name,
> >                 request->fence.context, request->fence.seqno,
> > -               engine->timeline->seqno + 1);
> > +               engine->timeline->seqno + 1,
> > +               intel_engine_get_seqno(engine));
> >   
> >       GEM_BUG_ON(!irqs_disabled());
> >       lockdep_assert_held(&engine->timeline->lock);
> > @@ -557,10 +562,11 @@ void __i915_request_unsubmit(struct i915_request *request)
> >   {
> >       struct intel_engine_cs *engine = request->engine;
> >   
> > -     GEM_TRACE("%s fence %llx:%d <- global_seqno %d\n",
> > -               request->engine->name,
> > +     GEM_TRACE("%s fence %llx:%d <- global_seqno %d, current %d\n",
> > +               engine->name,
> >                 request->fence.context, request->fence.seqno,
> > -               request->global_seqno);
> > +               request->global_seqno,
> > +               intel_engine_get_seqno(engine));
> >   
> >       GEM_BUG_ON(!irqs_disabled());
> >       lockdep_assert_held(&engine->timeline->lock);
> > diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
> > index ed2c833a8b20..b5235f52a81b 100644
> > --- a/drivers/gpu/drm/i915/intel_lrc.c
> > +++ b/drivers/gpu/drm/i915/intel_lrc.c
> > @@ -454,10 +454,11 @@ static void execlists_submit_ports(struct intel_engine_cs *engine)
> >                       desc = execlists_update_context(rq);
> >                       GEM_DEBUG_EXEC(port[n].context_id = upper_32_bits(desc));
> >   
> > -                     GEM_TRACE("%s in[%d]:  ctx=%d.%d, seqno=%x, prio=%d\n",
> > +                     GEM_TRACE("%s in[%d]:  ctx=%d.%d, seqno=%d (current %d), prio=%d\n",
> >                                 engine->name, n,
> >                                 port[n].context_id, count,
> >                                 rq->global_seqno,
> > +                               intel_engine_get_seqno(engine),
> >                                 rq_prio(rq));
> >               } else {
> >                       GEM_BUG_ON(!n);
> > @@ -999,10 +1000,11 @@ static void execlists_submission_tasklet(unsigned long data)
> >                                                       EXECLISTS_ACTIVE_USER));
> >   
> >                       rq = port_unpack(port, &count);
> > -                     GEM_TRACE("%s out[0]: ctx=%d.%d, seqno=%x, prio=%d\n",
> > +                     GEM_TRACE("%s out[0]: ctx=%d.%d, seqno=%d (current %d), prio=%d\n",
> >                                 engine->name,
> >                                 port->context_id, count,
> >                                 rq ? rq->global_seqno : 0,
> > +                               intel_engine_get_seqno(engine),
> >                                 rq ? rq_prio(rq) : 0);
> >   
> >                       /* Check the context/desc id for this event matches */
> > 
> 
> The only thing I am not sure if HWS seqno is interesting in the two 
> above. But if you think it is it doesn't harm much.

I was thinking consistency, anyway I had a global_seqno in the trace, we
would also have the current breadcrumb.
 
> Also in these two I had fence context:seqno instead to correlate easily 
> with (un)submit&co. That way when I select fence:context in an editor it 
> nicely highlights the whole flow relating to this request. Anyway:

Right, which I think was a very useful improvement.
 
> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

Do you want to take this patch into yours or apply this and then fixup
yours?
-Chris