[Intel-gfx] [PATCH 1/2] drm/i915: Keep a count of requests waiting for a slot on GPU

[Chris Wilson]

Quoting Tvrtko Ursulin (2017-11-22 12:46:21)
> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> 
> Keep a per-engine number of runnable (waiting for GPU time) requests.
> 
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_gem_request.c | 5 +++++
>  drivers/gpu/drm/i915/intel_engine_cs.c  | 5 +++--
>  drivers/gpu/drm/i915/intel_lrc.c        | 1 +
>  drivers/gpu/drm/i915/intel_ringbuffer.h | 8 ++++++++
>  4 files changed, 17 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem_request.c b/drivers/gpu/drm/i915/i915_gem_request.c
> index 7325469ce754..e3c74cafa7d4 100644
> --- a/drivers/gpu/drm/i915/i915_gem_request.c
> +++ b/drivers/gpu/drm/i915/i915_gem_request.c
> @@ -480,6 +480,9 @@ 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--;

Ok, so under engine->timeline->lock.

> +
>         spin_lock(&request->timeline->lock);
>         list_move_tail(&request->link, &timeline->requests);
>         spin_unlock(&request->timeline->lock);
> @@ -525,6 +528,8 @@ 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 d53680c08cb0..cc9d60130ddd 100644
> --- a/drivers/gpu/drm/i915/intel_engine_cs.c
> +++ b/drivers/gpu/drm/i915/intel_engine_cs.c
> @@ -1675,12 +1675,13 @@ 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, "    current seqno %x, last %x, hangcheck %x [%d ms], inflight %d\n",
> +       drm_printf(m, "    current 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,
> +                  INTEL_GEN(dev_priv) >= 8 ? engine->queued : -1);

Not gen8 specific, just add engine->queued++ to i9xx_submit_request().
-Chris