From c81d46138da658b6a4edc53d5d9aaf62d56d764b Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Fri, 1 Jul 2016 17:23:25 +0100 Subject: drm/i915: Convert trace-irq to the breadcrumb waiter If we convert the tracing over from direct use of ring->irq_get() and over to the breadcrumb infrastructure, we only have a single user of the ring->irq_get and so we will be able to simplify the driver routines (eliminating the redundant validation and irq refcounting). Process context is preferred over softirq (or even hardirq) for a couple of reasons: - we already utilize process context to have fast wakeup of a single client (i.e. the client waiting for the GPU inspects the seqno for itself following an interrupt to avoid the overhead of a context switch before it returns to userspace) - engine->irq_seqno() is not suitable for use from an softirq/hardirq context as we may require long waits (100-250us) to ensure the seqno write is posted before we read it from the CPU A signaling framework is a requirement for enabling dma-fences. v2: Move to a signaling framework based upon the waiter. v3: Track the first-signal to avoid having to walk the rbtree everytime. v4: Mark the signaler thread as RT priority to reduce latency in the indirect wakeups. v5: Make failure to allocate the thread fatal. v6: Rename kthreads to i915/signal:%u Signed-off-by: Chris Wilson Reviewed-by: Tvrtko Ursulin Link: http://patchwork.freedesktop.org/patch/msgid/1467390209-3576-16-git-send-email-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/i915_trace.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/gpu/drm/i915/i915_trace.h') diff --git a/drivers/gpu/drm/i915/i915_trace.h b/drivers/gpu/drm/i915/i915_trace.h index 3d13fde9..f59cf07 100644 --- a/drivers/gpu/drm/i915/i915_trace.h +++ b/drivers/gpu/drm/i915/i915_trace.h @@ -490,7 +490,7 @@ TRACE_EVENT(i915_gem_ring_dispatch, __entry->ring = req->engine->id; __entry->seqno = req->seqno; __entry->flags = flags; - i915_trace_irq_get(req->engine, req); + intel_engine_enable_signaling(req); ), TP_printk("dev=%u, ring=%u, seqno=%u, flags=%x", -- cgit v1.1