vppinfra: vectorized index to pointer function

Type: improvement
Change-Id: I05e1a8fa31761b113355123429d72da18881d4b0
Signed-off-by: Damjan Marion <damarion@cisco.com>

2 files changed, 312 insertions, 0 deletions

diff --git a/src/vppinfra/vector/index_to_ptr.h b/src/vppinfra/vector/index_to_ptr.h
new file mode 100644
index 00000000000..91de3546439
--- /dev/null
+++ b/src/vppinfra/vector/index_to_ptr.h
@@ -0,0 +1,254 @@
+/* SPDX-License-Identifier: Apache-2.0
+ * Copyright(c) 2021 Cisco Systems, Inc.
+ */
+
+#ifndef included_vector_index_to_ptr_h
+#define included_vector_index_to_ptr_h
+#include <vppinfra/clib.h>
+
+#ifdef CLIB_HAVE_VEC128
+static_always_inline void
+clib_index_to_ptr_u32x4 (u32 *indices, void **ptrs, i32 i, u64x2 ov, u8 shift)
+{
+  u32x4 iv4 = u32x4_load_unaligned (indices + i);
+  u64x2 pv2;
+  pv2 = u64x2_from_u32x4 (iv4);
+  u64x2_store_unaligned ((pv2 << shift) + ov, ptrs + i);
+#ifdef __aarch64__
+  pv2 = u64x2_from_u32x4_high (iv4);
+#else
+  pv2 = u64x2_from_u32x4 ((u32x4) u8x16_word_shift_right (iv4, 8));
+#endif
+  u64x2_store_unaligned ((pv2 << shift) + ov, ptrs + i + 2);
+}
+#endif
+
+/** \brief Convert array of indices to pointers with base and shift
+
+    @param indices source array of u32 indices
+    @param base base pointer
+    @param shift numbers of bits to be shifted
+    @param ptrs destinatin array of pointers
+    @param n_elts number of elements in the source array
+*/
+
+static_always_inline void
+clib_index_to_ptr_u32 (u32 *indices, void *base, u8 shift, void **ptrs,
+		       u32 n_elts)
+{
+#if defined CLIB_HAVE_VEC512
+  if (n_elts >= 8)
+    {
+      u64x8 off = u64x8_splat ((u64) base);
+      u64x8 b0, b1, b2, b3, b4, b5, b6, b7;
+
+      while (n_elts >= 64)
+	{
+	  b0 = u64x8_from_u32x8 (u32x8_load_unaligned (indices));
+	  b1 = u64x8_from_u32x8 (u32x8_load_unaligned (indices + 8));
+	  b2 = u64x8_from_u32x8 (u32x8_load_unaligned (indices + 16));
+	  b3 = u64x8_from_u32x8 (u32x8_load_unaligned (indices + 24));
+	  b4 = u64x8_from_u32x8 (u32x8_load_unaligned (indices + 32));
+	  b5 = u64x8_from_u32x8 (u32x8_load_unaligned (indices + 40));
+	  b6 = u64x8_from_u32x8 (u32x8_load_unaligned (indices + 48));
+	  b7 = u64x8_from_u32x8 (u32x8_load_unaligned (indices + 56));
+	  u64x8_store_unaligned ((b0 << shift) + off, ptrs);
+	  u64x8_store_unaligned ((b1 << shift) + off, ptrs + 8);
+	  u64x8_store_unaligned ((b2 << shift) + off, ptrs + 16);
+	  u64x8_store_unaligned ((b3 << shift) + off, ptrs + 24);
+	  u64x8_store_unaligned ((b4 << shift) + off, ptrs + 32);
+	  u64x8_store_unaligned ((b5 << shift) + off, ptrs + 40);
+	  u64x8_store_unaligned ((b6 << shift) + off, ptrs + 48);
+	  u64x8_store_unaligned ((b7 << shift) + off, ptrs + 56);
+	  ptrs += 64;
+	  indices += 64;
+	  n_elts -= 64;
+	}
+
+      if (n_elts == 0)
+	return;
+
+      if (n_elts >= 32)
+	{
+	  b0 = u64x8_from_u32x8 (u32x8_load_unaligned (indices));
+	  b1 = u64x8_from_u32x8 (u32x8_load_unaligned (indices + 8));
+	  b2 = u64x8_from_u32x8 (u32x8_load_unaligned (indices + 16));
+	  b3 = u64x8_from_u32x8 (u32x8_load_unaligned (indices + 24));
+	  u64x8_store_unaligned ((b0 << shift) + off, ptrs);
+	  u64x8_store_unaligned ((b1 << shift) + off, ptrs + 8);
+	  u64x8_store_unaligned ((b2 << shift) + off, ptrs + 16);
+	  u64x8_store_unaligned ((b3 << shift) + off, ptrs + 24);
+	  ptrs += 32;
+	  indices += 32;
+	  n_elts -= 32;
+	}
+      if (n_elts >= 16)
+	{
+	  b0 = u64x8_from_u32x8 (u32x8_load_unaligned (indices));
+	  b1 = u64x8_from_u32x8 (u32x8_load_unaligned (indices + 8));
+	  u64x8_store_unaligned ((b0 << shift) + off, ptrs);
+	  u64x8_store_unaligned ((b1 << shift) + off, ptrs + 8);
+	  ptrs += 16;
+	  indices += 16;
+	  n_elts -= 16;
+	}
+      if (n_elts > 8)
+	{
+	  b0 = u64x8_from_u32x8 (u32x8_load_unaligned (indices));
+	  u64x8_store_unaligned ((b0 << shift) + off, ptrs);
+	  ptrs += 8;
+	  indices += 8;
+	  n_elts -= 8;
+	}
+
+      b0 = u64x8_from_u32x8 (u32x8_load_unaligned (indices + n_elts - 8));
+      u64x8_store_unaligned ((b0 << shift) + off, ptrs + n_elts - 8);
+    }
+  else
+    {
+      u32 mask = pow2_mask (n_elts);
+      u64x8 r = u64x8_from_u32x8 (u32x8_mask_load_zero (indices, mask));
+      u64x8_mask_store ((r << shift) + u64x8_splat ((u64) base), ptrs, mask);
+      return;
+    }
+#elif defined CLIB_HAVE_VEC256
+  if (n_elts >= 4)
+    {
+      u64x4 off = u64x4_splat ((u64) base);
+      u64x4 b0, b1, b2, b3, b4, b5, b6, b7;
+
+      while (n_elts >= 32)
+	{
+	  b0 = u64x4_from_u32x4 (u32x4_load_unaligned (indices));
+	  b1 = u64x4_from_u32x4 (u32x4_load_unaligned (indices + 4));
+	  b2 = u64x4_from_u32x4 (u32x4_load_unaligned (indices + 8));
+	  b3 = u64x4_from_u32x4 (u32x4_load_unaligned (indices + 12));
+	  b4 = u64x4_from_u32x4 (u32x4_load_unaligned (indices + 16));
+	  b5 = u64x4_from_u32x4 (u32x4_load_unaligned (indices + 20));
+	  b6 = u64x4_from_u32x4 (u32x4_load_unaligned (indices + 24));
+	  b7 = u64x4_from_u32x4 (u32x4_load_unaligned (indices + 28));
+	  u64x4_store_unaligned ((b0 << shift) + off, ptrs);
+	  u64x4_store_unaligned ((b1 << shift) + off, ptrs + 4);
+	  u64x4_store_unaligned ((b2 << shift) + off, ptrs + 8);
+	  u64x4_store_unaligned ((b3 << shift) + off, ptrs + 12);
+	  u64x4_store_unaligned ((b4 << shift) + off, ptrs + 16);
+	  u64x4_store_unaligned ((b5 << shift) + off, ptrs + 20);
+	  u64x4_store_unaligned ((b6 << shift) + off, ptrs + 24);
+	  u64x4_store_unaligned ((b7 << shift) + off, ptrs + 28);
+	  ptrs += 32;
+	  indices += 32;
+	  n_elts -= 32;
+	}
+
+      if (n_elts == 0)
+	return;
+
+      if (n_elts >= 16)
+	{
+	  b0 = u64x4_from_u32x4 (u32x4_load_unaligned (indices));
+	  b1 = u64x4_from_u32x4 (u32x4_load_unaligned (indices + 4));
+	  b2 = u64x4_from_u32x4 (u32x4_load_unaligned (indices + 8));
+	  b3 = u64x4_from_u32x4 (u32x4_load_unaligned (indices + 12));
+	  u64x4_store_unaligned ((b0 << shift) + off, ptrs);
+	  u64x4_store_unaligned ((b1 << shift) + off, ptrs + 4);
+	  u64x4_store_unaligned ((b2 << shift) + off, ptrs + 8);
+	  u64x4_store_unaligned ((b3 << shift) + off, ptrs + 12);
+	  ptrs += 16;
+	  indices += 16;
+	  n_elts -= 16;
+	}
+      if (n_elts >= 8)
+	{
+	  b0 = u64x4_from_u32x4 (u32x4_load_unaligned (indices));
+	  b1 = u64x4_from_u32x4 (u32x4_load_unaligned (indices + 4));
+	  u64x4_store_unaligned ((b0 << shift) + off, ptrs);
+	  u64x4_store_unaligned ((b1 << shift) + off, ptrs + 4);
+	  ptrs += 8;
+	  indices += 8;
+	  n_elts -= 8;
+	}
+      if (n_elts > 4)
+	{
+	  b0 = u64x4_from_u32x4 (u32x4_load_unaligned (indices));
+	  u64x4_store_unaligned ((b0 << shift) + off, ptrs);
+	  ptrs += 4;
+	  indices += 4;
+	  n_elts -= 4;
+	}
+
+      b0 = u64x4_from_u32x4 (u32x4_load_unaligned (indices + n_elts - 4));
+      u64x4_store_unaligned ((b0 << shift) + off, ptrs + n_elts - 4);
+      return;
+    }
+#ifdef CLIB_HAVE_VEC256_MASK_LOAD_STORE
+  else
+    {
+      u32 mask = pow2_mask (n_elts);
+      u64x4 r = u64x4_from_u32x4 (u32x4_mask_load_zero (indices, mask));
+      u64x4_mask_store ((r << shift) + u64x4_splat ((u64) base), ptrs, mask);
+      return;
+    }
+#endif
+#elif defined(CLIB_HAVE_VEC128)
+  if (n_elts >= 4)
+    {
+      u64x2 ov = u64x2_splat ((u64) base);
+      u32 *i = (u32 *) indices;
+      void **p = (void **) ptrs;
+      u32 n = n_elts;
+
+      while (n >= 32)
+	{
+	  clib_index_to_ptr_u32x4 (indices, ptrs, 0, ov, shift);
+	  clib_index_to_ptr_u32x4 (indices, ptrs, 4, ov, shift);
+	  clib_index_to_ptr_u32x4 (indices, ptrs, 8, ov, shift);
+	  clib_index_to_ptr_u32x4 (indices, ptrs, 12, ov, shift);
+	  clib_index_to_ptr_u32x4 (indices, ptrs, 16, ov, shift);
+	  clib_index_to_ptr_u32x4 (indices, ptrs, 20, ov, shift);
+	  clib_index_to_ptr_u32x4 (indices, ptrs, 24, ov, shift);
+	  clib_index_to_ptr_u32x4 (indices, ptrs, 28, ov, shift);
+	  indices += 32;
+	  ptrs += 32;
+	  n -= 32;
+	}
+
+      if (n == 0)
+	return;
+
+      if (n >= 16)
+	{
+	  clib_index_to_ptr_u32x4 (indices, ptrs, 0, ov, shift);
+	  clib_index_to_ptr_u32x4 (indices, ptrs, 4, ov, shift);
+	  clib_index_to_ptr_u32x4 (indices, ptrs, 8, ov, shift);
+	  clib_index_to_ptr_u32x4 (indices, ptrs, 12, ov, shift);
+	  indices += 16;
+	  ptrs += 16;
+	  n -= 16;
+	}
+
+      if (n >= 8)
+	{
+	  clib_index_to_ptr_u32x4 (indices, ptrs, 0, ov, shift);
+	  clib_index_to_ptr_u32x4 (indices, ptrs, 4, ov, shift);
+	  indices += 8;
+	  ptrs += 8;
+	  n -= 8;
+	}
+
+      if (n > 4)
+	clib_index_to_ptr_u32x4 (indices, ptrs, 0, ov, shift);
+
+      clib_index_to_ptr_u32x4 (i, p, n_elts - 4, ov, shift);
+      return;
+    }
+#endif
+  while (n_elts)
+    {
+      ptrs[0] = base + ((u64) indices[0] << shift);
+      ptrs += 1;
+      indices += 1;
+      n_elts -= 1;
+    }
+}
+
+#endif
diff --git a/src/vppinfra/vector/test/index_to_ptr.c b/src/vppinfra/vector/test/index_to_ptr.c
new file mode 100644
index 00000000000..ae33020328a
--- /dev/null
+++ b/src/vppinfra/vector/test/index_to_ptr.c
@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: Apache-2.0
+ * Copyright(c) 2021 Cisco Systems, Inc.
+ */
+
+#include <vppinfra/format.h>
+#include <vppinfra/vector/test/test.h>
+#include <vppinfra/vector/index_to_ptr.h>
+
+typedef void (wrapper_fn) (u32 *indices, void *base, u8 shift, void **ptrs,
+			   u32 n_elts);
+
+__clib_test_fn void
+clib_index_to_ptr_u32_wrapper (u32 *indices, void *base, u8 shift, void **ptrs,
+			       u32 n_elts)
+{
+  clib_index_to_ptr_u32 (indices, base, shift, ptrs, n_elts);
+}
+
+static wrapper_fn *wfn = &clib_index_to_ptr_u32_wrapper;
+
+static clib_error_t *
+test_clib_index_to_ptr_u32 (clib_error_t *err)
+{
+  void *_ptrs[512 + 128], **ptrs = _ptrs + 64;
+  u32 _indices[512 + 128], *indices = _indices + 64;
+  u16 lengths[] = { 1,	3,  5,	7,  9,	15, 16, 17,  31, 32,
+		    33, 40, 41, 42, 63, 64, 65, 511, 512 };
+
+  for (int i = 0; i < ARRAY_LEN (_indices); i++)
+    _indices[i] = i;
+
+  for (int i = 0; i < ARRAY_LEN (lengths); i++)
+    {
+      u16 len = lengths[i];
+      u8 shift = 6;
+      void *base = (void *) 0x100000000 + i;
+
+      for (int j = -64; j < len + 64; j++)
+	ptrs[j] = (void *) 0xfefefefefefefefe;
+
+      wfn (indices, base, shift, ptrs, len);
+      for (int j = 0; j < len; j++)
+	{
+	  void *expected = base + ((u64) indices[j] << shift);
+	  if (ptrs[j] != expected)
+	    return clib_error_return (err,
+				      "testcase failed for length %u "
+				      "(offset %u, expected %p, found %p)",
+				      len, j, expected, ptrs[j]);
+	}
+    }
+  return err;
+}
+
+REGISTER_TEST (clib_index_to_ptr_u32) = {
+  .name = "clib_index_to_ptr_u32",
+  .fn = test_clib_index_to_ptr_u32,
+};