[RFC 10/17] drm/i915: Keep a count of requests waiting for a slot on GPU

Tvrtko Ursulin
2017-10-25T15:36:50Z

Keep a per-engine number of runnable (waiting for GPU time) requests.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
drivers/gpu/drm/i915/i915_gem_request.c | 5 +++++
drivers/gpu/drm/i915/intel_engine_cs.c | 6 ++++--
drivers/gpu/drm/i915/intel_lrc.c | 1 +
drivers/gpu/drm/i915/intel_ringbuffer.h | 8 ++++++++
4 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_request.c b/drivers/gpu/drm/i915/i915_gem_request.c
index 165988932c8b..00ad2c176e3e 100644
--- a/drivers/gpu/drm/i915/i915_gem_request.c
+++ b/drivers/gpu/drm/i915/i915_gem_request.c
@@ -478,6 +478,9 @@ void __i915_gem_request_submit(struct drm_i915_gem_request *request)
engine->emit_breadcrumb(request,
request->ring->vaddr + request->postfix);

+ GEM_BUG_ON(engine->queued == 0);
+ engine->queued--;
+
spin_lock(&request->timeline->lock);
list_move_tail(&request->link, &timeline->requests);
spin_unlock(&request->timeline->lock);
@@ -523,6 +526,8 @@ void __i915_gem_request_unsubmit(struct drm_i915_gem_request *request)
timeline = request->timeline;
GEM_BUG_ON(timeline == engine->timeline);

+ engine->queued++;
+
spin_lock(&timeline->lock);
list_move(&request->link, &timeline->requests);
spin_unlock(&timeline->lock);
diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
index 2998bc1d9ddf..c7f48c091dcd 100644
--- a/drivers/gpu/drm/i915/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/intel_engine_cs.c
@@ -1658,12 +1658,14 @@ void intel_engine_dump(struct intel_engine_cs *engine, struct drm_printer *m)
u64 addr;

drm_printf(m, "%s\n", engine->name);
- drm_printf(m, "\tcurrent seqno %x, last %x, hangcheck %x [%d ms], inflight %d\n",
+ drm_printf(m, "\tcurrent seqno %x, last %x, hangcheck %x [%d ms], inflight %d, queued %d\n",
intel_engine_get_seqno(engine),
intel_engine_last_submit(engine),
engine->hangcheck.seqno,
jiffies_to_msecs(jiffies - engine->hangcheck.action_timestamp),
- engine->timeline->inflight_seqnos);
+ engine->timeline->inflight_seqnos,
+ i915_modparams.enable_execlists || INTEL_GEN(dev_priv) >= 9 ?
+ engine->queued : -1);
drm_printf(m, "\tReset count: %d\n",
i915_reset_engine_count(error, engine));

diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index c727340c0b46..fcdd1c52f5ae 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -938,6 +938,7 @@ static void insert_request(struct intel_engine_cs *engine,
{
struct i915_priolist *p = lookup_priolist(engine, pt, prio);

+ engine->queued++;
list_add_tail(&pt->link, &ptr_mask_bits(p, 1)->requests);
if (ptr_unmask_bits(p, 1))
tasklet_hi_schedule(&engine->execlists.irq_tasklet);
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 66fcb45a14cd..3b1dbcbb9d1f 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -303,6 +303,14 @@ struct intel_engine_cs {

struct intel_ring *buffer;
struct intel_timeline *timeline;
+ /**
+ * @queued: Number of runnable requests submitted to the backend.
+ *
+ * Count of requests waiting for the GPU to execute them.
+ *
+ * Valid only with execlists and GuC submissions backends.
+ */
+ unsigned int queued;

struct intel_render_state *render_state;