[dpdk-dev] [PATCH v2 3/6] fib: introduce AVX512 lookup

Vladimir Medvedkin vladimir.medvedkin at intel.com
Thu May 14 14:28:27 CEST 2020


Add new lookup implementation for DIR24_8 algorithm using
AVX512 instruction set

Signed-off-by: Vladimir Medvedkin <vladimir.medvedkin at intel.com>
---
 lib/librte_fib/Makefile         |  14 +++++
 lib/librte_fib/dir24_8.c        |  74 +++++++++++++++++++++++++
 lib/librte_fib/dir24_8_avx512.h | 116 ++++++++++++++++++++++++++++++++++++++++
 lib/librte_fib/meson.build      |  10 ++++
 lib/librte_fib/rte_fib.h        |   3 +-
 5 files changed, 216 insertions(+), 1 deletion(-)
 create mode 100644 lib/librte_fib/dir24_8_avx512.h

diff --git a/lib/librte_fib/Makefile b/lib/librte_fib/Makefile
index 1dd2a49..0b6c825 100644
--- a/lib/librte_fib/Makefile
+++ b/lib/librte_fib/Makefile
@@ -20,3 +20,17 @@ SRCS-$(CONFIG_RTE_LIBRTE_FIB) := rte_fib.c rte_fib6.c dir24_8.c trie.c
 SYMLINK-$(CONFIG_RTE_LIBRTE_FIB)-include := rte_fib.h rte_fib6.h
 
 include $(RTE_SDK)/mk/rte.lib.mk
+
+CC_AVX512F_SUPPORT=$(shell $(CC) -mavx512f -dM -E - </dev/null 2>&1 | \
+grep -q __AVX512F__ && echo 1)
+
+CC_AVX512DQ_SUPPORT=$(shell $(CC) -mavx512dq -dM -E - </dev/null 2>&1 | \
+grep -q __AVX512DQ__ && echo 1)
+
+ifeq ($(CC_AVX512F_SUPPORT), 1)
+	ifeq ($(CC_AVX512DQ_SUPPORT), 1)
+		CFLAGS_dir24_8.o += -mavx512f
+		CFLAGS_dir24_8.o += -mavx512dq
+		CFLAGS_dir24_8.o += -DCC_AVX512_SUPPORT
+	endif
+endif
diff --git a/lib/librte_fib/dir24_8.c b/lib/librte_fib/dir24_8.c
index 825d061..443873c 100644
--- a/lib/librte_fib/dir24_8.c
+++ b/lib/librte_fib/dir24_8.c
@@ -245,6 +245,62 @@ dir24_8_lookup_bulk_uni(void *p, const uint32_t *ips,
 	}
 }
 
+#ifdef CC_AVX512_SUPPORT
+
+#include "dir24_8_avx512.h"
+
+static void
+rte_dir24_8_vec_lookup_bulk_1b(void *p, const uint32_t *ips,
+	uint64_t *next_hops, const unsigned int n)
+{
+	uint32_t i;
+	for (i = 0; i < (n / 16); i++)
+		dir24_8_vec_lookup_x16(p, ips + i * 16, next_hops + i * 16,
+			sizeof(uint8_t));
+
+	dir24_8_lookup_bulk_1b(p, ips + i * 16, next_hops + i * 16,
+		n - i * 16);
+}
+
+static void
+rte_dir24_8_vec_lookup_bulk_2b(void *p, const uint32_t *ips,
+	uint64_t *next_hops, const unsigned int n)
+{
+	uint32_t i;
+	for (i = 0; i < (n / 16); i++)
+		dir24_8_vec_lookup_x16(p, ips + i * 16, next_hops + i * 16,
+			sizeof(uint16_t));
+
+	dir24_8_lookup_bulk_2b(p, ips + i * 16, next_hops + i * 16,
+		n - i * 16);
+}
+
+static void
+rte_dir24_8_vec_lookup_bulk_4b(void *p, const uint32_t *ips,
+	uint64_t *next_hops, const unsigned int n)
+{
+	uint32_t i;
+	for (i = 0; i < (n / 16); i++)
+		dir24_8_vec_lookup_x16(p, ips + i * 16, next_hops + i * 16,
+			sizeof(uint32_t));
+
+	dir24_8_lookup_bulk_4b(p, ips + i * 16, next_hops + i * 16,
+		n - i * 16);
+}
+
+static void
+rte_dir24_8_vec_lookup_bulk_8b(void *p, const uint32_t *ips,
+	uint64_t *next_hops, const unsigned int n)
+{
+	uint32_t i;
+	for (i = 0; i < (n / 8); i++)
+		dir24_8_vec_lookup_x8_8b(p, ips + i * 8, next_hops + i * 8);
+
+	dir24_8_lookup_bulk_8b(p, ips + i * 8, next_hops + i * 8, n - i * 8);
+}
+
+#endif /* CC_AVX512_SUPPORT */
+
 rte_fib_lookup_fn_t
 dir24_8_get_lookup_fn(void *p, enum rte_fib_dir24_8_lookup_type type)
 {
@@ -285,6 +341,24 @@ dir24_8_get_lookup_fn(void *p, enum rte_fib_dir24_8_lookup_type type)
 		}
 	case RTE_FIB_DIR24_8_SCALAR_UNI:
 		return dir24_8_lookup_bulk_uni;
+#ifdef CC_AVX512_SUPPORT
+	case RTE_FIB_DIR24_8_VECTOR:
+		if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_AVX512F) <= 0)
+			return NULL;
+
+		switch (nh_sz) {
+		case RTE_FIB_DIR24_8_1B:
+			return rte_dir24_8_vec_lookup_bulk_1b;
+		case RTE_FIB_DIR24_8_2B:
+			return rte_dir24_8_vec_lookup_bulk_2b;
+		case RTE_FIB_DIR24_8_4B:
+			return rte_dir24_8_vec_lookup_bulk_4b;
+		case RTE_FIB_DIR24_8_8B:
+			return rte_dir24_8_vec_lookup_bulk_8b;
+		default:
+			return NULL;
+		}
+#endif
 	default:
 		return NULL;
 	}
diff --git a/lib/librte_fib/dir24_8_avx512.h b/lib/librte_fib/dir24_8_avx512.h
new file mode 100644
index 0000000..e3792e0
--- /dev/null
+++ b/lib/librte_fib/dir24_8_avx512.h
@@ -0,0 +1,116 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2020 Intel Corporation
+ */
+
+#ifndef _DIR248_AVX512_H_
+#define _DIR248_AVX512_H_
+
+#include <rte_vect.h>
+
+static __rte_always_inline void
+dir24_8_vec_lookup_x16(void *p, const uint32_t *ips,
+	uint64_t *next_hops, int size)
+{
+	struct dir24_8_tbl *dp = (struct dir24_8_tbl *)p;
+	__mmask16 msk_ext;
+	__mmask16 exp_msk = 0x5555;
+	__m512i ip_vec, idxes, res, bytes;
+	const __m512i zero = _mm512_set1_epi32(0);
+	const __m512i lsb = _mm512_set1_epi32(1);
+	const __m512i lsbyte_msk = _mm512_set1_epi32(0xff);
+	__m512i tmp1, tmp2, res_msk;
+	__m256i tmp256;
+	/* used to mask gather values if size is 1/2 (8/16 bit next hops) */
+	if (size == sizeof(uint8_t))
+		res_msk = _mm512_set1_epi32(UINT8_MAX);
+	else if (size == sizeof(uint16_t))
+		res_msk = _mm512_set1_epi32(UINT16_MAX);
+
+	ip_vec = _mm512_loadu_si512(ips);
+	/* mask 24 most significant bits */
+	idxes = _mm512_srli_epi32(ip_vec, 8);
+
+	/**
+	 * lookup in tbl24
+	 * Put it inside branch to make compiler happy with -O0
+	 */
+	if (size == sizeof(uint8_t)) {
+		res = _mm512_i32gather_epi32(idxes, (const int *)dp->tbl24, 1);
+		res = _mm512_and_epi32(res, res_msk);
+	} else if (size == sizeof(uint16_t)) {
+		res = _mm512_i32gather_epi32(idxes, (const int *)dp->tbl24, 2);
+		res = _mm512_and_epi32(res, res_msk);
+	} else
+		res = _mm512_i32gather_epi32(idxes, (const int *)dp->tbl24, 4);
+
+	/* get extended entries indexes */
+	msk_ext = _mm512_test_epi32_mask(res, lsb);
+
+	if (msk_ext != 0) {
+		idxes = _mm512_srli_epi32(res, 1);
+		idxes = _mm512_slli_epi32(idxes, 8);
+		bytes = _mm512_and_epi32(ip_vec, lsbyte_msk);
+		idxes = _mm512_maskz_add_epi32(msk_ext, idxes, bytes);
+		if (size == sizeof(uint8_t)) {
+			idxes = _mm512_mask_i32gather_epi32(zero, msk_ext,
+				idxes, (const int *)dp->tbl8, 1);
+			idxes = _mm512_and_epi32(idxes, res_msk);
+		} else if (size == sizeof(uint16_t)) {
+			idxes = _mm512_mask_i32gather_epi32(zero, msk_ext,
+				idxes, (const int *)dp->tbl8, 2);
+			idxes = _mm512_and_epi32(idxes, res_msk);
+		} else
+			idxes = _mm512_mask_i32gather_epi32(zero, msk_ext,
+				idxes, (const int *)dp->tbl8, 4);
+
+		res = _mm512_mask_blend_epi32(msk_ext, res, idxes);
+	}
+
+	res = _mm512_srli_epi32(res, 1);
+	tmp1 = _mm512_maskz_expand_epi32(exp_msk, res);
+	tmp256 = _mm512_extracti32x8_epi32(res, 1);
+	tmp2 = _mm512_maskz_expand_epi32(exp_msk,
+		_mm512_castsi256_si512(tmp256));
+	_mm512_storeu_si512(next_hops, tmp1);
+	_mm512_storeu_si512(next_hops + 8, tmp2);
+}
+
+static __rte_always_inline void
+dir24_8_vec_lookup_x8_8b(void *p, const uint32_t *ips,
+	uint64_t *next_hops)
+{
+	struct dir24_8_tbl *dp = (struct dir24_8_tbl *)p;
+	const __m512i zero = _mm512_set1_epi32(0);
+	const __m512i lsbyte_msk = _mm512_set1_epi64(0xff);
+	const __m512i lsb = _mm512_set1_epi64(1);
+	__m512i res, idxes, bytes;
+	__m256i idxes_256, ip_vec;
+	__mmask8 msk_ext;
+
+	ip_vec = _mm256_loadu_si256((const void *)ips);
+	/* mask 24 most significant bits */
+	idxes_256 = _mm256_srli_epi32(ip_vec, 8);
+
+	/* lookup in tbl24 */
+	res = _mm512_i32gather_epi64(idxes_256, (const void *)dp->tbl24, 8);
+
+	/* get extended entries indexes */
+	msk_ext = _mm512_test_epi64_mask(res, lsb);
+
+	if (msk_ext != 0) {
+		bytes = _mm512_cvtepi32_epi64(ip_vec);
+		idxes = _mm512_srli_epi64(res, 1);
+		idxes = _mm512_slli_epi64(idxes, 8);
+		bytes = _mm512_and_epi64(bytes, lsbyte_msk);
+		idxes = _mm512_maskz_add_epi64(msk_ext, idxes, bytes);
+		idxes = _mm512_mask_i64gather_epi64(zero, msk_ext, idxes,
+			(const void *)dp->tbl8, 8);
+
+		res = _mm512_mask_blend_epi64(msk_ext, res, idxes);
+	}
+
+	res = _mm512_srli_epi64(res, 1);
+	_mm512_storeu_si512(next_hops, res);
+}
+
+#endif /* _DIR248_AVX512_H_ */
diff --git a/lib/librte_fib/meson.build b/lib/librte_fib/meson.build
index 771828f..86b1d4a 100644
--- a/lib/librte_fib/meson.build
+++ b/lib/librte_fib/meson.build
@@ -5,3 +5,13 @@
 sources = files('rte_fib.c', 'rte_fib6.c', 'dir24_8.c', 'trie.c')
 headers = files('rte_fib.h', 'rte_fib6.h')
 deps += ['rib']
+
+if dpdk_conf.has('RTE_ARCH_X86')
+	if cc.has_argument('-mavx512f')
+		cflags += '-DCC_AVX512_SUPPORT'
+		cflags += '-mavx512f'
+	endif
+	if cc.has_argument('-mavx512dq')
+		cflags += '-mavx512dq'
+	endif
+endif
diff --git a/lib/librte_fib/rte_fib.h b/lib/librte_fib/rte_fib.h
index db35685..2919d13 100644
--- a/lib/librte_fib/rte_fib.h
+++ b/lib/librte_fib/rte_fib.h
@@ -54,7 +54,8 @@ enum rte_fib_dir24_8_nh_sz {
 enum rte_fib_dir24_8_lookup_type {
 	RTE_FIB_DIR24_8_SCALAR_MACRO,
 	RTE_FIB_DIR24_8_SCALAR_INLINE,
-	RTE_FIB_DIR24_8_SCALAR_UNI
+	RTE_FIB_DIR24_8_SCALAR_UNI,
+	RTE_FIB_DIR24_8_VECTOR
 };
 
 /** FIB configuration structure */
-- 
2.7.4



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