Chris Wilson <ch...@chris-wilson.co.uk> writes:
> Only declare a missed interrupt if we find that the GPU is idle with
> waiters and a hangcheck interval has passed in which no new user
> interrupts have been raised.
>
> Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk>
> Cc: Mika Kuoppala <mika.kuopp...@intel.com>
> ---
> drivers/gpu/drm/i915/i915_debugfs.c | 11 +++++++----
> drivers/gpu/drm/i915/i915_irq.c | 7 ++++++-
> drivers/gpu/drm/i915/intel_ringbuffer.h | 2 ++
> 3 files changed, 15 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c
> b/drivers/gpu/drm/i915/i915_debugfs.c
> index b421b53ca128..966fc022418c 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -730,10 +730,10 @@ static int i915_gem_request_info(struct seq_file *m,
> void *data)
> static void i915_ring_seqno_info(struct seq_file *m,
> struct intel_engine_cs *ring)
> {
> - if (ring->get_seqno) {
> - seq_printf(m, "Current sequence (%s): %x\n",
> - ring->name, ring->get_seqno(ring));
> - }
> + seq_printf(m, "Current sequence (%s): %x\n",
> + ring->name, ring->get_seqno(ring));
> + seq_printf(m, "Current user interrupts (%s): %x\n",
> + ring->name, READ_ONCE(ring->user_interrupts));
> }
>
> static int i915_gem_seqno_info(struct seq_file *m, void *data)
> @@ -1361,6 +1361,9 @@ static int i915_hangcheck_info(struct seq_file *m, void
> *unused)
> seq_printf(m, "%s:\n", ring->name);
> seq_printf(m, "\tseqno = %x [current %x]\n",
> ring->hangcheck.seqno, seqno[i]);
> + seq_printf(m, "\tuser interrupts = %x [current %x]\n",
> + ring->hangcheck.user_interrupts,
> + ring->user_interrupts);
> seq_printf(m, "\tACTHD = 0x%08llx [current 0x%08llx]\n",
> (long long)ring->hangcheck.acthd,
> (long long)acthd[i]);
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index 07bc2cdd6252..978eebcf4594 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -1000,6 +1000,7 @@ static void notify_ring(struct intel_engine_cs *ring)
> return;
>
> trace_i915_gem_request_notify(ring);
> + ring->user_interrupts++;
>
For 100% accuracy we would neeb (w)mb() here?
Now you only do READ_ONCE on reader side which is not
enough.
I admit that the chances to hit this are slim to none,
but is this all to avoid mb on irq path?
-Mika
> wake_up_all(&ring->irq_queue);
> }
> @@ -3097,6 +3098,7 @@ static void i915_hangcheck_elapsed(struct work_struct
> *work)
> for_each_ring(ring, dev_priv, i) {
> u64 acthd;
> u32 seqno;
> + unsigned user_interrupts;
> bool busy = true;
>
> semaphore_clear_deadlocks(dev_priv);
> @@ -3113,6 +3115,7 @@ static void i915_hangcheck_elapsed(struct work_struct
> *work)
>
> acthd = intel_ring_get_active_head(ring);
> seqno = ring->get_seqno(ring);
> + user_interrupts = READ_ONCE(ring->user_interrupts);
>
> if (ring->hangcheck.seqno == seqno) {
> if (ring_idle(ring, seqno)) {
> @@ -3120,7 +3123,8 @@ static void i915_hangcheck_elapsed(struct work_struct
> *work)
>
> if (waitqueue_active(&ring->irq_queue)) {
> /* Issue a wake-up to catch stuck h/w.
> */
> - if (!test_and_set_bit(ring->id,
> &dev_priv->gpu_error.missed_irq_rings)) {
> + if (ring->hangcheck.user_interrupts ==
> user_interrupts &&
> + !test_and_set_bit(ring->id,
> &dev_priv->gpu_error.missed_irq_rings)) {
> if
> (!(dev_priv->gpu_error.test_irq_rings & intel_ring_flag(ring)))
> DRM_ERROR("Hangcheck
> timer elapsed... %s idle\n",
> ring->name);
> @@ -3187,6 +3191,7 @@ static void i915_hangcheck_elapsed(struct work_struct
> *work)
>
> ring->hangcheck.seqno = seqno;
> ring->hangcheck.acthd = acthd;
> + ring->hangcheck.user_interrupts = user_interrupts;
> busy_count += busy;
> }
>
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h
> b/drivers/gpu/drm/i915/intel_ringbuffer.h
> index e1797d42054c..b30ad99a54bf 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.h
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
> @@ -90,6 +90,7 @@ struct intel_ring_hangcheck {
> u64 acthd;
> u64 max_acthd;
> u32 seqno;
> + unsigned user_interrupts;
> int score;
> enum intel_ring_hangcheck_action action;
> int deadlock;
> @@ -301,6 +302,7 @@ struct intel_engine_cs {
> * inspecting request list.
> */
> u32 last_submitted_seqno;
> + unsigned user_interrupts;
>
> bool gpu_caches_dirty;
>
> --
> 2.7.0.rc3
>
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> Intel-gfx@lists.freedesktop.org
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