This commit adds lib/hash-aarch64.h to implement hash for aarch64.
It is based on aarch64 built-in CRC32c intrinsics, which accelerates
hash function for datapath performance.
test:
1. "test-hash" case passed in aarch64 platform.
2. OVS-DPDK datapth performance test was run(NIC to NIC).
Test bed: aarch64(Centriq 2400) platform.
Test case: DPCLS forwarding(disable EMC + avg 10 subtable lookups)
Test result: improve around 10%.
Signed-off-by: Yanqin Wei <yanqin....@arm.com>
---
lib/automake.mk | 1 +
lib/hash-aarch64.h | 151 +++++++++++++++++++++++++++++++++++++++++++++
lib/hash.h | 5 +-
3 files changed, 156 insertions(+), 1 deletion(-)
create mode 100644 lib/hash-aarch64.h
diff --git a/lib/automake.mk b/lib/automake.mk
index b1ff495ff..ba1041095 100644
--- a/lib/automake.mk
+++ b/lib/automake.mk
@@ -100,6 +100,7 @@ lib_libopenvswitch_la_SOURCES = \
lib/guarded-list.h \
lib/hash.c \
lib/hash.h \
+ lib/hash-aarch64.h \
lib/hindex.c \
lib/hindex.h \
lib/hmap.c \
diff --git a/lib/hash-aarch64.h b/lib/hash-aarch64.h
new file mode 100644
index 000000000..6993e2a66
--- /dev/null
+++ b/lib/hash-aarch64.h
@@ -0,0 +1,151 @@
+/*
+ * Copyright (c) 2019 Arm Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* This header implements HASH operation primitives on aarch64. */
+#ifndef HASH_AARCH64_H
+#define HASH_AARCH64_H 1
+
+#ifndef HASH_H
+#error "This header should only be included indirectly via hash.h."
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <arm_acle.h>
+
+static inline uint32_t hash_add(uint32_t hash, uint32_t data)
+{
+ return __crc32cw(hash, data);
+}
+
+/* Add the halves of 'data' in the memory order. */
+static inline uint32_t hash_add64(uint32_t hash, uint64_t data)
+{
+ return __crc32cd(hash, data);
+}
+
+static inline uint32_t hash_finish(uint32_t hash, uint64_t final)
+{
+ /* The finishing multiplier 0x805204f3 has been experimentally
+ * derived to pass the testsuite hash tests. */
+ hash = __crc32cd(hash, final) * 0x805204f3;
+ return hash ^ hash >> 16; /* Increase entropy in LSBs. */
+}
+
+/* Returns the hash of the 'n' 32-bit words at 'p_', starting from 'basis'.
+ * We access 'p_' as a uint64_t pointer.
+ *
+ * This is inlined for the compiler to have access to the 'n_words', which
+ * in many cases is a constant. */
+static inline uint32_t
+hash_words_inline(const uint32_t p_[], size_t n_words, uint32_t basis)
+{
+ const uint64_t *p = (const void *)p_;
+ uint32_t hash1 = basis;
+ uint32_t hash2 = 0;
+ uint32_t hash3 = n_words;
+ const uint32_t *endp = (const uint32_t *)p + n_words;
+ const uint64_t *limit = p + n_words / 2 - 3;
+
+ while (p <= limit) {
+ hash1 = __crc32cd(hash1, p[0]);
+ hash2 = __crc32cd(hash2, p[1]);
+ hash3 = __crc32cd(hash3, p[2]);
+ p += 3;
+ }
+ switch (endp - (const uint32_t *)p) {
+ case 1:
+ hash1 = __crc32cw(hash1, *(const uint32_t *)&p[0]);
+ break;
+ case 2:
+ hash1 = __crc32cd(hash1, p[0]);
+ break;
+ case 3:
+ hash1 = __crc32cd(hash1, p[0]);
+ hash2 = __crc32cw(hash2, *(const uint32_t *)&p[1]);
+ break;
+ case 4:
+ hash1 = __crc32cd(hash1, p[0]);
+ hash2 = __crc32cd(hash2, p[1]);
+ break;
+ case 5:
+ hash1 = __crc32cd(hash1, p[0]);
+ hash2 = __crc32cd(hash2, p[1]);
+ hash3 = __crc32cw(hash3, *(const uint32_t *)&p[2]);
+ break;
+ }
+ return hash_finish(hash1, (uint64_t)hash2 << 32 | hash3);
+}
+
+/* A simpler version for 64-bit data.
+ * 'n_words' is the count of 64-bit words, basis is 64 bits. */
+static inline uint32_t
+hash_words64_inline(const uint64_t p[], size_t n_words, uint32_t basis)
+{
+ uint32_t hash1 = basis;
+ uint32_t hash2 = 0;
+ uint32_t hash3 = n_words;
+ const uint64_t *endp = p + n_words;
+ const uint64_t *limit = endp - 3;
+
+ while (p <= limit) {
+ hash1 = __crc32cd(hash1, p[0]);
+ hash2 = __crc32cd(hash2, p[1]);
+ hash3 = __crc32cd(hash3, p[2]);
+ p += 3;
+ }
+ switch (endp - p) {
+ case 1:
+ hash1 = __crc32cd(hash1, p[0]);
+ break;
+ case 2:
+ hash1 = __crc32cd(hash1, p[0]);
+ hash2 = __crc32cd(hash2, p[1]);
+ break;
+ }
+ return hash_finish(hash1, (uint64_t)hash2 << 32 | hash3);
+}
+
+static inline uint32_t hash_uint64_basis(const uint64_t x,
+ const uint32_t basis)
+{
+ /* '23' chosen to mix bits enough for the test-hash to pass. */
+ return hash_finish(hash_add64(basis, x), 23);
+}
+
+static inline uint32_t hash_uint64(const uint64_t x)
+{
+ return hash_uint64_basis(x, 0);
+}
+
+static inline uint32_t hash_2words(uint32_t x, uint32_t y)
+{
+ return hash_uint64((uint64_t)y << 32 | x);
+}
+
+static inline uint32_t hash_pointer(const void *p, uint32_t basis)
+{
+ return hash_uint64_basis((uint64_t) (uintptr_t) p, basis);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* hash-aarch64.h */
+
diff --git a/lib/hash.h b/lib/hash.h
index a642a1e97..6898719ca 100644
--- a/lib/hash.h
+++ b/lib/hash.h
@@ -98,7 +98,10 @@ static inline uint32_t hash_add_words64(uint32_t, const
uint64_t *, size_t);
static inline uint32_t hash_add_bytes32(uint32_t, const uint32_t *, size_t);
static inline uint32_t hash_add_bytes64(uint32_t, const uint64_t *, size_t);
-#if !(defined(__SSE4_2__) && defined(__x86_64__))
+#if (defined(__ARM_FEATURE_CRC32) && defined(__aarch64__))
+#include "hash-aarch64.h"
+
+#elif !(defined(__SSE4_2__) && defined(__x86_64__))
/* Mhash-based implementation. */
static inline uint32_t hash_add(uint32_t hash, uint32_t data)
--
2.17.1
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