• Chris Wilson's avatar
    drm/i915/execlists: Force preemption · 3a7a92ab
    Chris Wilson authored
    If the preempted context takes too long to relinquish control, e.g. it
    is stuck inside a shader with arbitration disabled, evict that context
    with an engine reset. This ensures that preemptions are reasonably
    responsive, providing a tighter QoS for the more important context at
    the cost of flagging unresponsive contexts more frequently (i.e. instead
    of using an ~10s hangcheck, we now evict at ~100ms).  The challenge of
    lies in picking a timeout that can be reasonably serviced by HW for
    typical workloads, balancing the existing clients against the needs for
    responsiveness.
    
    Note that coupled with timeslicing, this will lead to rapid GPU "hang"
    detection with multiple active contexts vying for GPU time.
    
    The forced preemption mechanism can be compiled out with
    
    	./scripts/config --set-val DRM_I915_PREEMPT_TIMEOUT 0
    Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
    Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
    Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
    Reviewed-by: default avatarMika Kuoppala <mika.kuoppala@linux.intel.com>
    Link: https://patchwork.freedesktop.org/patch/msgid/20191023133108.21401-2-chris@chris-wilson.co.uk
    3a7a92ab
i915_params.h 3.36 KB