Mesa (master): anv/gen11+: Calculate pixel hashing tables instead of hardcoding.

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Module: Mesa
Branch: master
Commit: 11febd50e2816779f32faff030d98141d3085897
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=11febd50e2816779f32faff030d98141d3085897

Author: Francisco Jerez <currojerez at riseup.net>
Date:   Wed Jan 13 22:53:13 2021 -0800

anv/gen11+: Calculate pixel hashing tables instead of hardcoding.

See commit "iris/gen11+: Calculate pixel hashing tables instead of
hardcoding." for the rationale.

Reviewed-by: Jason Ekstrand <jason at jlekstrand.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/8749>

---

 src/intel/vulkan/genX_state.c | 96 +++++++++++++++++++++----------------------
 1 file changed, 48 insertions(+), 48 deletions(-)

diff --git a/src/intel/vulkan/genX_state.c b/src/intel/vulkan/genX_state.c
index 9dc9fb4c4b6..f779bf3a3e9 100644
--- a/src/intel/vulkan/genX_state.c
+++ b/src/intel/vulkan/genX_state.c
@@ -36,6 +36,45 @@
 
 #include "vk_util.h"
 
+/**
+ * Compute an \p n x \p m pixel hashing table usable as slice, subslice or
+ * pixel pipe hashing table.  The resulting table is the cyclic repetition of
+ * a fixed pattern with periodicity equal to \p period.
+ *
+ * If \p index is specified to be equal to \p period, a 2-way hashing table
+ * will be generated such that indices 0 and 1 are returned for the following
+ * fractions of entries respectively:
+ *
+ *   p_0 = ceil(period / 2) / period
+ *   p_1 = floor(period / 2) / period
+ *
+ * If \p index is even and less than \p period, a 3-way hashing table will be
+ * generated such that indices 0, 1 and 2 are returned for the following
+ * fractions of entries:
+ *
+ *   p_0 = (ceil(period / 2) - 1) / period
+ *   p_1 = floor(period / 2) / period
+ *   p_2 = 1 / period
+ *
+ * The equations above apply if \p flip is equal to 0, if it is equal to 1 p_0
+ * and p_1 will be swapped for the result.  Note that in the context of pixel
+ * pipe hashing this can be always 0 on Gen12 platforms, since the hardware
+ * transparently remaps logical indices found on the table to physical pixel
+ * pipe indices from the highest to lowest EU count.
+ */
+UNUSED static void
+calculate_pixel_hashing_table(unsigned n, unsigned m,
+                              unsigned period, unsigned index, bool flip,
+                              uint32_t *p)
+{
+   for (unsigned i = 0; i < n; i++) {
+      for (unsigned j = 0; j < m; j++) {
+         const unsigned k = (i + j) % period;
+         p[j + m * i] = (k == index ? 2 : (k & 1) ^ flip);
+      }
+   }
+}
+
 static void
 genX(emit_slice_hashing_state)(struct anv_device *device,
                                struct anv_batch *batch)
@@ -43,60 +82,21 @@ genX(emit_slice_hashing_state)(struct anv_device *device,
    device->slice_hash = (struct anv_state) { 0 };
 
 #if GEN_GEN == 11
-   const unsigned *ppipe_subslices = device->info.ppipe_subslices;
-   int subslices_delta = ppipe_subslices[0] - ppipe_subslices[1];
-   if (subslices_delta == 0)
-      return;
+   assert(device->info.ppipe_subslices[2] == 0);
+
+   if (device->info.ppipe_subslices[0] == device->info.ppipe_subslices[1])
+     return;
 
    unsigned size = GENX(SLICE_HASH_TABLE_length) * 4;
    device->slice_hash =
       anv_state_pool_alloc(&device->dynamic_state_pool, size, 64);
 
-   struct GENX(SLICE_HASH_TABLE) table0 = {
-      .Entry = {
-         { 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1 },
-         { 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1 },
-         { 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0 },
-         { 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1 },
-         { 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1 },
-         { 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0 },
-         { 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1 },
-         { 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1 },
-         { 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0 },
-         { 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1 },
-         { 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1 },
-         { 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0 },
-         { 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1 },
-         { 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1 },
-         { 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0 },
-         { 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1 }
-      }
-   };
-
-   struct GENX(SLICE_HASH_TABLE) table1 = {
-      .Entry = {
-         { 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0 },
-         { 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0 },
-         { 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1 },
-         { 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0 },
-         { 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0 },
-         { 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1 },
-         { 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0 },
-         { 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0 },
-         { 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1 },
-         { 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0 },
-         { 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0 },
-         { 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1 },
-         { 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0 },
-         { 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0 },
-         { 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1 },
-         { 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0 }
-      }
-   };
+   const bool flip = device->info.ppipe_subslices[0] <
+                     device->info.ppipe_subslices[1];
+   struct GENX(SLICE_HASH_TABLE) table;
+   calculate_pixel_hashing_table(16, 16, 3, 3, flip, table.Entry[0]);
 
-   const struct GENX(SLICE_HASH_TABLE) *table =
-      subslices_delta < 0 ? &table0 : &table1;
-   GENX(SLICE_HASH_TABLE_pack)(NULL, device->slice_hash.map, table);
+   GENX(SLICE_HASH_TABLE_pack)(NULL, device->slice_hash.map, &table);
 
    anv_batch_emit(batch, GENX(3DSTATE_SLICE_TABLE_STATE_POINTERS), ptr) {
       ptr.SliceHashStatePointerValid = true;