1. 21 May, 2015 5 commits
    • Chris Wilson's avatar
      drm/i915: Implement inter-engine read-read optimisations · b4716185
      Chris Wilson authored
      Currently, we only track the last request globally across all engines.
      This prevents us from issuing concurrent read requests on e.g. the RCS
      and BCS engines (or more likely the render and media engines). Without
      semaphores, we incur costly stalls as we synchronise between rings -
      greatly impacting the current performance of Broadwell versus Haswell in
      certain workloads (like video decode). With the introduction of
      reference counted requests, it is much easier to track the last request
      per ring, as well as the last global write request so that we can
      optimise inter-engine read read requests (as well as better optimise
      certain CPU waits).
      
      v2: Fix inverted readonly condition for nonblocking waits.
      v3: Handle non-continguous engine array after waits
      v4: Rebase, tidy, rewrite ring list debugging
      v5: Use obj->active as a bitfield, it looks cool
      v6: Micro-optimise, mostly involving moving code around
      v7: Fix retire-requests-upto for execlists (and multiple rq->ringbuf)
      v8: Rebase
      v9: Refactor i915_gem_object_sync() to allow the compiler to better
      optimise it.
      
      Benchmark: igt/gem_read_read_speed
      hsw:gt3e (with semaphores):
      Before: Time to read-read 1024k:		275.794µs
      After:  Time to read-read 1024k:		123.260µs
      
      hsw:gt3e (w/o semaphores):
      Before: Time to read-read 1024k:		230.433µs
      After:  Time to read-read 1024k:		124.593µs
      
      bdw-u (w/o semaphores):             Before          After
      Time to read-read 1x1:            26.274µs       10.350µs
      Time to read-read 128x128:        40.097µs       21.366µs
      Time to read-read 256x256:        77.087µs       42.608µs
      Time to read-read 512x512:       281.999µs      181.155µs
      Time to read-read 1024x1024:    1196.141µs     1118.223µs
      Time to read-read 2048x2048:    5639.072µs     5225.837µs
      Time to read-read 4096x4096:   22401.662µs    21137.067µs
      Time to read-read 8192x8192:   89617.735µs    85637.681µs
      
      Testcase: igt/gem_concurrent_blit (read-read and friends)
      Cc: Lionel Landwerlin <lionel.g.landwerlin@linux.intel.com>
      Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
      Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
      Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> [v8]
      [danvet: s/\<rq\>/req/g]
      Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
      b4716185
    • Daniel Vetter's avatar
      drm/i915: s/\<rq\>/req/g · eed29a5b
      Daniel Vetter authored
      The merged seqno->request conversion from John called request
      variables req, but some (not all) of Chris' recent patches changed
      those to just rq. We've had a lenghty (and inconclusive) discussion on
      irc which is the more meaningful name with maybe at most a slight bias
      towards req.
      
      Given that the "don't change names without good reason to avoid
      conflicts" rule applies, so lets go back to a req everywhere for
      consistency. I'll sed any patches for which this will cause conflicts
      before applying.
      
      Cc: Chris Wilson <chris@chris-wilson.co.uk>
      Cc: John Harrison <John.C.Harrison@Intel.com>
      [danvet: s/origina/merged/ as pointed out by Chris - the first
      mass-conversion patch was from Chris, the merged one from John.]
      Signed-off-by: default avatarDaniel Vetter <daniel.vetter@intel.com>
      eed29a5b
    • Imre Deak's avatar
      drm/i915/skl: enable WaForceContextSaveRestoreNonCoherent · 8ea6f892
      Imre Deak authored
      v2:
      - set the override disable flag too on stepping F0 (mika)
      Signed-off-by: default avatarImre Deak <imre.deak@intel.com>
      Reviewed-by: default avatarMika Kuoppala <mika.kuoppala@intel.com>
      Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
      8ea6f892
    • Imre Deak's avatar
      drm/i915/bxt: fix WaForceContextSaveRestoreNonCoherent on steppings B0+ · 2a0ee94f
      Imre Deak authored
      On B0 and C0 steppings the workaround enable bit would be overriden by
      default, so the overriding must be disabled.
      
      The WA was added in
      commit 83a24979
      Author: Nick Hoath <nicholas.hoath@intel.com>
      Date:   Fri Apr 10 13:12:26 2015 +0100
      
          drm/i915/bxt: Add WaForceContextSaveRestoreNonCoherent
      Spotted-by: default avatarMika Kuoppala <mika.kuoppala@intel.com>
      Signed-off-by: default avatarImre Deak <imre.deak@intel.com>
      Reviewed-by: default avatarMika Kuoppala <mika.kuoppala@intel.com>
      Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
      2a0ee94f
    • Chris Wilson's avatar
      drm/i915: Force clean compilation with -Werror · 118182e9
      Chris Wilson authored
      Our driver compiles clean (nowadays thanks to 0day) but for me, at least,
      it would be beneficial if the compiler threw an error rather than a
      warning when it found a piece of suspect code. (I use this to
      compile-check patch series and want to break on the first compiler error
      in order to fix the patch.)
      
      v2: Kick off a new "Debugging" submenu for i915.ko
      Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
      Acked-by: default avatarJani Nikula <jani.nikula@intel.com>
      [danvet: Add "DRM i915" to the menu name as requested by Chris.]
      Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
      118182e9
  2. 20 May, 2015 35 commits