<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <a class="bz_bug_link bz_status_ASSIGNED " title="ASSIGNED --- - [PNV/HSW/BDW bisected]igt/gem_exec_lut_handle is slow" href="https://bugs.freedesktop.org/show_bug.cgi?id=78023#c5">Comment # 5</a> on <a class="bz_bug_link bz_status_ASSIGNED " title="ASSIGNED --- - [PNV/HSW/BDW bisected]igt/gem_exec_lut_handle is slow" href="https://bugs.freedesktop.org/show_bug.cgi?id=78023">bug 78023</a> from <a class="email" href="mailto:chris@chris-wilson.co.uk" title="Chris Wilson <chris@chris-wilson.co.uk>"> Chris Wilson</a> <pre>The root cause is ppgtt: commit 1f70999f9052f5a1b0ce1a55aff3808f2ec9fe42 Author: Chris Wilson <<a href="mailto:chris@chris-wilson.co.uk">chris@chris-wilson.co.uk</a>> Date: Mon Jan 27 22:43:07 2014 +0000 drm/i915: Prevent recursion by retiring requests when the ring is full As the VM do not track activity of objects and instead use a large hammer to forcibly idle and evict all of their associated objects when one is released, it is possible for that to cause a recursion when we need to wait for free space on a ring and call retire requests. (intel_ring_begin -> intel_ring_wait_request -> i915_gem_retire_requests_ring -> i915_gem_context_free -> i915_gem_evict_vm -> i915_gpu_idle -> intel_ring_begin etc) In order to remove the requirement for calling retire-requests from intel_ring_wait_request, we have to inline a couple of steps from retiring requests, notably we have to record the position of the request we wait for and use that to update the available ring space. Signed-off-by: Chris Wilson <<a href="mailto:chris@chris-wilson.co.uk">chris@chris-wilson.co.uk</a>> Reviewed-by: Ville Syrjälä <<a href="mailto:ville.syrjala@linux.intel.com">ville.syrjala@linux.intel.com</a>> Signed-off-by: Daniel Vetter <<a href="mailto:daniel.vetter@ffwll.ch">daniel.vetter@ffwll.ch</a>> removes the i915_gem_retire_requests_ring() when we run out of ring space, and this test has no explicit request retiring and so depends upon this implicit retire.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> <li>You are on the CC list for the bug.</li> </ul> </body> </html>