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authorChris Wilson2013-04-08 08:28:40 -0500
committerGreg Kroah-Hartman2013-05-11 15:54:02 -0500
commitcbb83bb7bea7effffbd4097b3b355780e07f273d (patch)
tree64c8b2e06059fa28810afc206e9e4f019128e2ec
parentb578b3a82d830e2170d403b1fb29b649e26a48fb (diff)
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drm/i915: Use MLC (l3$) for context objects
commit 4615d4c9e27eda42c3e965f208a4b4065841498c upstream. Enabling context support increases SwapBuffers latency by about 20% (measured on an i7-3720qm). We can offset that loss slightly by enabling faster caching for the contexts. As they are not backed by any particular cache (such as the sampler or render caches) our only option is to select the generic mid-level cache. This reduces the latency of the swap by about 5%. Oddly this effect can be observed running smokin-guns on IVB at 1280x1024: Using BLT copies for swaps: 151.67 fps Using Render copies for swaps (unpatched): 141.70 fps With contexts disabled: 150.23 fps With contexts in L3$: 150.77 fps Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Ben Widawsky <ben@bwidawsk.net> Cc: Kenneth Graunke <kenneth@whitecape.org> Reviewed-by: Kenneth Graunke <kenneth@whitecape.org> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/gpu/drm/i915/i915_gem_context.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index a3f06bcad551..d8ac0a3a1743 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -157,6 +157,13 @@ create_hw_context(struct drm_device *dev,
157 return ERR_PTR(-ENOMEM); 157 return ERR_PTR(-ENOMEM);
158 } 158 }
159 159
160 if (INTEL_INFO(dev)->gen >= 7) {
161 ret = i915_gem_object_set_cache_level(ctx->obj,
162 I915_CACHE_LLC_MLC);
163 if (ret)
164 goto err_out;
165 }
166
160 /* The ring associated with the context object is handled by the normal 167 /* The ring associated with the context object is handled by the normal
161 * object tracking code. We give an initial ring value simple to pass an 168 * object tracking code. We give an initial ring value simple to pass an
162 * assertion in the context switch code. 169 * assertion in the context switch code.