vppinfra: new vectorized ip checksum functions incl. csum_and_copy

Type: improvement
Change-Id: Id5810b7f4a6d6e4ce16b73c235b50db5d475ebf7
Signed-off-by: Damjan Marion <damarion@cisco.com>

1 files changed, 339 insertions, 0 deletions

diff --git a/src/vppinfra/vector/ip_csum.h b/src/vppinfra/vector/ip_csum.h
new file mode 100644
index 00000000000..2cea9b448ea
--- /dev/null
+++ b/src/vppinfra/vector/ip_csum.h
@@ -0,0 +1,339 @@
+/* SPDX-License-Identifier: Apache-2.0
+ * Copyright(c) 2021 Cisco Systems, Inc.
+ */
+
+#ifndef included_vector_ip_csum_h
+#define included_vector_ip_csum_h
+#include <vppinfra/clib.h>
+typedef struct
+{
+  u64 sum;
+  u8 odd;
+} clib_ip_csum_t;
+
+#if defined(CLIB_HAVE_VEC128)
+static_always_inline u64x2
+clib_ip_csum_cvt_and_add_4 (u32x4 v)
+{
+  return ((u64x2) u32x4_interleave_lo ((u32x4) v, u32x4_zero ()) +
+	  (u64x2) u32x4_interleave_hi ((u32x4) v, u32x4_zero ()));
+}
+static_always_inline u64
+clib_ip_csum_hadd_2 (u64x2 v)
+{
+  return v[0] + v[1];
+}
+#endif
+
+#if defined(CLIB_HAVE_VEC256)
+static_always_inline u64x4
+clib_ip_csum_cvt_and_add_8 (u32x8 v)
+{
+  return ((u64x4) u32x8_interleave_lo ((u32x8) v, u32x8_zero ()) +
+	  (u64x4) u32x8_interleave_hi ((u32x8) v, u32x8_zero ()));
+}
+static_always_inline u64
+clib_ip_csum_hadd_4 (u64x4 v)
+{
+  return clib_ip_csum_hadd_2 (u64x4_extract_lo (v) + u64x4_extract_hi (v));
+}
+#endif
+
+#if defined(CLIB_HAVE_VEC512)
+static_always_inline u64x8
+clib_ip_csum_cvt_and_add_16 (u32x16 v)
+{
+  return ((u64x8) u32x16_interleave_lo ((u32x16) v, u32x16_zero ()) +
+	  (u64x8) u32x16_interleave_hi ((u32x16) v, u32x16_zero ()));
+}
+static_always_inline u64
+clib_ip_csum_hadd_8 (u64x8 v)
+{
+  return clib_ip_csum_hadd_4 (u64x8_extract_lo (v) + u64x8_extract_hi (v));
+}
+#endif
+
+static_always_inline void
+clib_ip_csum_inline (clib_ip_csum_t *c, u8 *dst, u8 *src, u16 count,
+		     int is_copy)
+{
+  if (c->odd)
+    {
+      c->odd = 0;
+      c->sum += (u16) src[0] << 8;
+      count--;
+      src++;
+      if (is_copy)
+	dst++[0] = src[0];
+    }
+
+#if defined(CLIB_HAVE_VEC512)
+  u64x8 sum8 = {};
+
+  while (count >= 512)
+    {
+      u32x16u *s = (u32x16u *) src;
+      sum8 += clib_ip_csum_cvt_and_add_16 (s[0]);
+      sum8 += clib_ip_csum_cvt_and_add_16 (s[1]);
+      sum8 += clib_ip_csum_cvt_and_add_16 (s[2]);
+      sum8 += clib_ip_csum_cvt_and_add_16 (s[3]);
+      sum8 += clib_ip_csum_cvt_and_add_16 (s[8]);
+      sum8 += clib_ip_csum_cvt_and_add_16 (s[5]);
+      sum8 += clib_ip_csum_cvt_and_add_16 (s[6]);
+      sum8 += clib_ip_csum_cvt_and_add_16 (s[7]);
+      count -= 512;
+      src += 512;
+      if (is_copy)
+	{
+	  u32x16u *d = (u32x16u *) dst;
+	  d[0] = s[0];
+	  d[1] = s[1];
+	  d[2] = s[2];
+	  d[3] = s[3];
+	  d[4] = s[4];
+	  d[5] = s[5];
+	  d[6] = s[6];
+	  d[7] = s[7];
+	  dst += 512;
+	}
+    }
+
+  while (count >= 64)
+    {
+      u32x16u *s = (u32x16u *) src;
+      sum8 += clib_ip_csum_cvt_and_add_16 (s[0]);
+      count -= 64;
+      src += 64;
+      if (is_copy)
+	{
+	  u32x16u *d = (u32x16u *) dst;
+	  d[0] = s[0];
+	  dst += 512;
+	}
+    }
+
+#ifdef CLIB_HAVE_VEC256_MASK_LOAD_STORE
+  if (count)
+    {
+      u64 mask = pow2_mask (count);
+      u32x16 v = (u32x16) u8x64_mask_load_zero (src, mask);
+      sum8 += clib_ip_csum_cvt_and_add_16 (v);
+      c->odd = count & 1;
+      if (is_copy)
+	u32x16_mask_store (v, dst, mask);
+    }
+  c->sum += clib_ip_csum_hadd_8 (sum8);
+  return;
+#endif
+
+  c->sum += clib_ip_csum_hadd_8 (sum8);
+#elif defined(CLIB_HAVE_VEC256)
+  u64x4 sum4 = {};
+
+  while (count >= 256)
+    {
+      u32x8u *s = (u32x8u *) src;
+      sum4 += clib_ip_csum_cvt_and_add_8 (s[0]);
+      sum4 += clib_ip_csum_cvt_and_add_8 (s[1]);
+      sum4 += clib_ip_csum_cvt_and_add_8 (s[2]);
+      sum4 += clib_ip_csum_cvt_and_add_8 (s[3]);
+      sum4 += clib_ip_csum_cvt_and_add_8 (s[4]);
+      sum4 += clib_ip_csum_cvt_and_add_8 (s[5]);
+      sum4 += clib_ip_csum_cvt_and_add_8 (s[6]);
+      sum4 += clib_ip_csum_cvt_and_add_8 (s[7]);
+      count -= 256;
+      src += 256;
+      if (is_copy)
+	{
+	  u32x8u *d = (u32x8u *) dst;
+	  d[0] = s[0];
+	  d[1] = s[1];
+	  d[2] = s[2];
+	  d[3] = s[3];
+	  d[4] = s[4];
+	  d[5] = s[5];
+	  d[6] = s[6];
+	  d[7] = s[7];
+	  dst += 256;
+	}
+    }
+
+  while (count >= 32)
+    {
+      u32x8u *s = (u32x8u *) src;
+      sum4 += clib_ip_csum_cvt_and_add_8 (s[0]);
+      count -= 32;
+      src += 32;
+      if (is_copy)
+	{
+	  u32x8u *d = (u32x8u *) dst;
+	  d[0] = s[0];
+	  dst += 32;
+	}
+    }
+
+#ifdef CLIB_HAVE_VEC256_MASK_LOAD_STORE
+  if (count)
+    {
+      u32 mask = pow2_mask (count);
+      u32x8 v = (u32x8) u8x32_mask_load_zero (src, mask);
+      sum4 += clib_ip_csum_cvt_and_add_8 (v);
+      c->odd = count & 1;
+      if (is_copy)
+	u32x8_mask_store (v, dst, mask);
+    }
+  c->sum += clib_ip_csum_hadd_4 (sum4);
+  return;
+#endif
+
+  c->sum += clib_ip_csum_hadd_4 (sum4);
+#elif defined(CLIB_HAVE_VEC128)
+  u64x2 sum2 = {};
+
+  while (count >= 128)
+    {
+      u32x4u *s = (u32x4u *) src;
+      sum2 += clib_ip_csum_cvt_and_add_4 (s[0]);
+      sum2 += clib_ip_csum_cvt_and_add_4 (s[1]);
+      sum2 += clib_ip_csum_cvt_and_add_4 (s[2]);
+      sum2 += clib_ip_csum_cvt_and_add_4 (s[3]);
+      sum2 += clib_ip_csum_cvt_and_add_4 (s[4]);
+      sum2 += clib_ip_csum_cvt_and_add_4 (s[5]);
+      sum2 += clib_ip_csum_cvt_and_add_4 (s[6]);
+      sum2 += clib_ip_csum_cvt_and_add_4 (s[7]);
+      count -= 128;
+      src += 128;
+      if (is_copy)
+	{
+	  u32x4u *d = (u32x4u *) dst;
+	  d[0] = s[0];
+	  d[1] = s[1];
+	  d[2] = s[2];
+	  d[3] = s[3];
+	  d[4] = s[4];
+	  d[5] = s[5];
+	  d[6] = s[6];
+	  d[7] = s[7];
+	  dst += 128;
+	}
+    }
+
+  while (count >= 16)
+    {
+      u32x4u *s = (u32x4u *) src;
+      sum2 += clib_ip_csum_cvt_and_add_4 (s[0]);
+      count -= 16;
+      src += 16;
+      if (is_copy)
+	{
+	  u32x4u *d = (u32x4u *) dst;
+	  d[0] = s[0];
+	  dst += 16;
+	}
+    }
+  c->sum += clib_ip_csum_hadd_2 (sum2);
+#else
+  while (count >= 4)
+    {
+      u32 v = *((u32 *) src);
+      c->sum += v;
+      count -= 4;
+      src += 4;
+      if (is_copy)
+	{
+	  *(u32 *) dst = v;
+	  dst += 4;
+	}
+    }
+#endif
+  while (count >= 2)
+    {
+      u16 v = *((u16 *) src);
+      c->sum += v;
+      count -= 2;
+      src += 2;
+      if (is_copy)
+	{
+	  *(u16 *) dst = v;
+	  dst += 2;
+	}
+    }
+
+  if (count)
+    {
+      c->odd = 1;
+      c->sum += (u16) src[0];
+      if (is_copy)
+	dst[0] = src[0];
+    }
+}
+
+static_always_inline u16
+clib_ip_csum_fold (clib_ip_csum_t *c)
+{
+  u64 sum = c->sum;
+#if defined(__x86_64__) && defined(__BMI2__)
+  u64 tmp = sum;
+  asm volatile(
+    /* using ADC is much faster than mov, shift, add sequence
+     * compiler produces */
+    "shr	$32, %[sum]			\n\t"
+    "add	%k[tmp], %k[sum]		\n\t"
+    "mov	$16, %k[tmp]			\n\t"
+    "shrx	%k[tmp], %k[sum], %k[tmp]	\n\t"
+    "adc	%w[tmp], %w[sum]		\n\t"
+    "adc	$0, %w[sum]			\n\t"
+    : [ sum ] "+&r"(sum), [ tmp ] "+&r"(tmp));
+#else
+  sum = ((u32) sum) + (sum >> 32);
+  sum = ((u16) sum) + (sum >> 16);
+  sum = ((u16) sum) + (sum >> 16);
+#endif
+  return (~((u16) sum));
+}
+
+static_always_inline void
+clib_ip_csum_chunk (clib_ip_csum_t *c, u8 *src, u16 count)
+{
+  return clib_ip_csum_inline (c, 0, src, count, 0);
+}
+
+static_always_inline void
+clib_ip_csum_and_copy_chunk (clib_ip_csum_t *c, u8 *src, u8 *dst, u16 count)
+{
+  return clib_ip_csum_inline (c, dst, src, count, 1);
+}
+
+static_always_inline u16
+clib_ip_csum (u8 *src, u16 count)
+{
+  clib_ip_csum_t c = {};
+  if (COMPILE_TIME_CONST (count) && count == 12)
+    {
+      for (int i = 0; i < 3; i++)
+	c.sum += ((u32 *) src)[i];
+    }
+  else if (COMPILE_TIME_CONST (count) && count == 20)
+    {
+      for (int i = 0; i < 5; i++)
+	c.sum += ((u32 *) src)[i];
+    }
+  else if (COMPILE_TIME_CONST (count) && count == 40)
+    {
+      for (int i = 0; i < 10; i++)
+	c.sum += ((u32 *) src)[i];
+    }
+  else
+    clib_ip_csum_inline (&c, 0, src, count, 0);
+  return clib_ip_csum_fold (&c);
+}
+
+static_always_inline u16
+clib_ip_csum_and_copy (u8 *dst, u8 *src, u16 count)
+{
+  clib_ip_csum_t c = {};
+  clib_ip_csum_inline (&c, dst, src, count, 1);
+  return clib_ip_csum_fold (&c);
+}
+
+#endif