From b76687910693b1f6c32a3251a8291d67363bba34 Mon Sep 17 00:00:00 2001 From: Damien Lespiau Date: Sat, 14 Feb 2015 18:30:29 +0000 Subject: [PATCH] drm/i915/skl: Tune IZ hashing when subslices are unbalanced When one EU is disabled in a particular subslice, we can tune how the work is spread between subslices to improve EU utilization. v2: - Use a bitfield to record which subslice(s) has(have) 7 EUs. That will also make the machinery work if several sublices have 7 EUs. (Jeff Mcgee) - Only apply the different hashing algorithm if the slice is effectively unbalanced by checking there's a single subslice with 7 EUs. (Jeff Mcgee) v3: Fix typo in comment (Jeff Mcgee) Issue: VIZ-3845 Cc: Jeff Mcgee Reviewed-by: Jeff Mcgee Signed-off-by: Damien Lespiau Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/i915_dma.c | 17 ++++++++++--- drivers/gpu/drm/i915/i915_drv.h | 2 ++ drivers/gpu/drm/i915/i915_reg.h | 2 ++ drivers/gpu/drm/i915/intel_ringbuffer.c | 45 ++++++++++++++++++++++++++++++++- 4 files changed, 62 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c index 9a365b40b50e..f9992ca11d10 100644 --- a/drivers/gpu/drm/i915/i915_dma.c +++ b/drivers/gpu/drm/i915/i915_dma.c @@ -650,13 +650,24 @@ static void intel_device_info_runtime_init(struct drm_device *dev) continue; for (ss = 0; ss < ss_max; ss++) { + u32 n_disabled; + if (ss_disable & (0x1 << ss)) /* skip disabled subslice */ continue; - info->eu_total += eu_max - - hweight8(eu_disable[s] >> - (ss * eu_max)); + n_disabled = hweight8(eu_disable[s] >> + (ss * eu_max)); + + /* + * Record which subslice(s) has(have) 7 EUs. we + * can tune the hash used to spread work among + * subslices if they are unbalanced. + */ + if (eu_max - n_disabled == 7) + info->subslice_7eu[s] |= 1 << ss; + + info->eu_total += eu_max - n_disabled; } } diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 61d41abde2e9..4280d0b292da 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -700,6 +700,8 @@ struct intel_device_info { u8 subslice_per_slice; u8 eu_total; u8 eu_per_subslice; + /* For each slice, which subslice(s) has(have) 7 EUs (bitfield)? */ + u8 subslice_7eu[3]; u8 has_slice_pg:1; u8 has_subslice_pg:1; u8 has_eu_pg:1; diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index 5fab90c84c5d..c2124119692d 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -1351,6 +1351,8 @@ enum skl_disp_power_wells { #define GEN6_WIZ_HASHING_16x4 GEN6_WIZ_HASHING(1, 0) #define GEN6_WIZ_HASHING_MASK GEN6_WIZ_HASHING(1, 1) #define GEN6_TD_FOUR_ROW_DISPATCH_DISABLE (1 << 5) +#define GEN9_IZ_HASHING_MASK(slice) (0x3 << (slice * 2)) +#define GEN9_IZ_HASHING(slice, val) ((val) << (slice * 2)) #define GFX_MODE 0x02520 #define GFX_MODE_GEN7 0x0229c diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c index 4570fe172b79..665985d5fcf4 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.c +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c @@ -1002,6 +1002,49 @@ static int gen9_init_workarounds(struct intel_engine_cs *ring) return 0; } +static int skl_tune_iz_hashing(struct intel_engine_cs *ring) +{ + struct drm_device *dev = ring->dev; + struct drm_i915_private *dev_priv = dev->dev_private; + u8 vals[3] = { 0, 0, 0 }; + unsigned int i; + + for (i = 0; i < 3; i++) { + u8 ss; + + /* + * Only consider slices where one, and only one, subslice has 7 + * EUs + */ + if (hweight8(dev_priv->info.subslice_7eu[i]) != 1) + continue; + + /* + * subslice_7eu[i] != 0 (because of the check above) and + * ss_max == 4 (maximum number of subslices possible per slice) + * + * -> 0 <= ss <= 3; + */ + ss = ffs(dev_priv->info.subslice_7eu[i]) - 1; + vals[i] = 3 - ss; + } + + if (vals[0] == 0 && vals[1] == 0 && vals[2] == 0) + return 0; + + /* Tune IZ hashing. See intel_device_info_runtime_init() */ + WA_SET_FIELD_MASKED(GEN7_GT_MODE, + GEN9_IZ_HASHING_MASK(2) | + GEN9_IZ_HASHING_MASK(1) | + GEN9_IZ_HASHING_MASK(0), + GEN9_IZ_HASHING(2, vals[2]) | + GEN9_IZ_HASHING(1, vals[1]) | + GEN9_IZ_HASHING(0, vals[0])); + + return 0; +} + + static int skl_init_workarounds(struct intel_engine_cs *ring) { struct drm_device *dev = ring->dev; @@ -1014,7 +1057,7 @@ static int skl_init_workarounds(struct intel_engine_cs *ring) WA_SET_BIT_MASKED(HIZ_CHICKEN, BDW_HIZ_POWER_COMPILER_CLOCK_GATING_DISABLE); - return 0; + return skl_tune_iz_hashing(ring); } int init_workarounds_ring(struct intel_engine_cs *ring) -- 2.11.0