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

Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxxxxxxx> · Thu, 29 Mar 2018 10:43:11 +0100

On 29/03/2018 09:55, Chris Wilson wrote:
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@xxxxxxxxxxxxxxxxxx>
---
   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@xxxxxxxxx>

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

You can go with this one and I'll send a follow up at some point.

Regards,

Tvrtko

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