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drm/i915: Use eLLC/LLC by default when available

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DRI clients really should be using MOCS to get fine grained streaming
cache controls. With that note, I *hope* that this patch doesn't improve
performance overwhelmingly, because if it does - it means there is a
problem elsewhere.

In any case, the kernel, and old userspace should get some benefit from
this, so let's do it. eLLC is always a good default, and really not
using it is the special case for MOCS.

References: http://www.intel.com/newsroom/kits/restricted/ha$well!/pdfs/4th_Gen_Intel_Core_PressBriefing_5-29.pdf (page 57)

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Ben Widawsky 2013-07-04 11:02:06 -07:00 committed by Daniel Vetter
parent 59124506ba
commit 4d15c145a6
1 changed files with 16 additions and 1 deletions
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17
drivers/gpu/drm/i915/i915_gem_gtt.c
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@ -53,6 +53,7 @@
#define HSW_CACHEABILITY_CONTROL(bits) ((((bits) & 0x7) << 1) | \
(((bits) & 0x8) << (11 - 3)))
#define HSW_WB_LLC_AGE0 HSW_CACHEABILITY_CONTROL(0x3)
#define HSW_WB_ELLC_LLC_AGE0 HSW_CACHEABILITY_CONTROL(0xb)
static gen6_gtt_pte_t gen6_pte_encode(dma_addr_t addr,
enum i915_cache_level level)
@ -109,6 +110,18 @@ static gen6_gtt_pte_t hsw_pte_encode(dma_addr_t addr,
return pte;
}
static gen6_gtt_pte_t iris_pte_encode(dma_addr_t addr,
enum i915_cache_level level)
{
gen6_gtt_pte_t pte = GEN6_PTE_VALID;
pte |= HSW_PTE_ADDR_ENCODE(addr);
if (level != I915_CACHE_NONE)
pte |= HSW_WB_ELLC_LLC_AGE0;
return pte;
}
static void gen6_write_pdes(struct i915_hw_ppgtt *ppgtt)
{
struct drm_i915_private *dev_priv = ppgtt->dev->dev_private;
@ -861,7 +874,9 @@ int i915_gem_gtt_init(struct drm_device *dev)
} else {
gtt->gtt_probe = gen6_gmch_probe;
gtt->gtt_remove = gen6_gmch_remove;
if (IS_HASWELL(dev))
if (IS_HASWELL(dev) && dev_priv->ellc_size)
gtt->pte_encode = iris_pte_encode;
else if (IS_HASWELL(dev))
gtt->pte_encode = hsw_pte_encode;
else if (IS_VALLEYVIEW(dev))
gtt->pte_encode = byt_pte_encode;