On Mon, Aug 26, 2013 at 01:46:21PM +0100, Chris Wilson wrote: > So that we can find the callers who introduce a ring stall. A single > ring stall is not too unwelcome, the right issue becomes when they start > to interlock and prevent any concurrent work. That, however, is a little > tricker to detect with a mere tracepoint!
I was staring at the semaphore code a bit recently, and I was wondering if it would make sense to do a manual seqno check (against the ring's current seqno, not just the last sync_seqno) before we decide to add the semaphore into the ring? > > Signed-off-by: Chris Wilson <[email protected]> > --- > drivers/gpu/drm/i915/i915_gem.c | 2 ++ > drivers/gpu/drm/i915/i915_trace.h | 19 +++++++++++++++++++ > 2 files changed, 21 insertions(+) > > diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c > index 85537d1..0122278 100644 > --- a/drivers/gpu/drm/i915/i915_gem.c > +++ b/drivers/gpu/drm/i915/i915_gem.c > @@ -2698,6 +2698,8 @@ i915_gem_object_sync(struct drm_i915_gem_object *obj, > if (ret) > return ret; > > + trace_i915_gem_object_sync(obj, to); > + > ret = to->sync_to(to, from, seqno); > if (!ret) > /* We use last_read_seqno because sync_to() > diff --git a/drivers/gpu/drm/i915/i915_trace.h > b/drivers/gpu/drm/i915/i915_trace.h > index feaacbb..728c43b 100644 > --- a/drivers/gpu/drm/i915/i915_trace.h > +++ b/drivers/gpu/drm/i915/i915_trace.h > @@ -33,6 +33,25 @@ TRACE_EVENT(i915_gem_object_create, > TP_printk("obj=%p, size=%u", __entry->obj, __entry->size) > ); > > +TRACE_EVENT(i915_gem_object_sync, > + TP_PROTO(struct drm_i915_gem_object *obj, struct intel_ring_buffer > *to), > + TP_ARGS(obj, to), > + > + TP_STRUCT__entry( > + __field(struct drm_i915_gem_object *, obj) > + __field(u32, sync_from) > + __field(u32, sync_to) > + ), > + > + TP_fast_assign( > + __entry->obj = obj; > + __entry->sync_from = obj->ring->id; > + __entry->sync_to = to->id; > + ), > + > + TP_printk("obj=%p, sync-from=%u, sync-to=%u", __entry->obj, > __entry->sync_from, __entry->sync_to) > +); > + > TRACE_EVENT(i915_vma_bind, > TP_PROTO(struct i915_vma *vma, bool mappable), > TP_ARGS(vma, mappable), > -- > 1.8.4.rc3 > > _______________________________________________ > Intel-gfx mailing list > [email protected] > http://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Ville Syrjälä Intel OTC _______________________________________________ Intel-gfx mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/intel-gfx
