+++ /dev/null
-/*
- * Copyright (c) 2017 Intel and/or its affiliates.
- * 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.
- */
-
-/**
- * vppinfra already includes tons of different hash tables.
- * MagLev flow table is a bit different. It has to be very efficient
- * for both writing and reading operations. But it does not need to
- * be 100% reliable (write can fail). It also needs to recycle
- * old entries in a lazy way.
- *
- * This hash table is the most dummy hash table you can do.
- * Fixed total size, fixed bucket size.
- * Advantage is that it could be very efficient (maybe).
- *
- */
-
-#ifndef KP_PLUGIN_KP_KPHASH_H_
-#define KP_PLUGIN_KP_KPHASH_H_
-
-#include <vnet/vnet.h>
-#include <vppinfra/xxhash.h>
-#include <vppinfra/crc32.h>
-
-/*
- * @brief Number of entries per bucket.
- */
-#define KPHASH_ENTRY_PER_BUCKET 4
-
-#define KP_HASH_DO_NOT_USE_SSE_BUCKETS 0
-
-/**
- * 32 bits integer comparison for running values.
- * 1 > 0 is true. But 1 > 0xffffffff also is.
- */
-#define clib_u32_loop_gt(a, b) (((u32)(a)) - ((u32)(b)) < 0x7fffffff)
-
-/*
- * @brief One bucket contains 4 entries.
- * Each bucket takes one 64B cache line in memory.
- */
-typedef struct {
- CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
- u32 hash[KPHASH_ENTRY_PER_BUCKET];
- u32 timeout[KPHASH_ENTRY_PER_BUCKET];
- u32 vip[KPHASH_ENTRY_PER_BUCKET];
- u32 value[KPHASH_ENTRY_PER_BUCKET];
-} kp_hash_bucket_t;
-
-typedef struct {
- u32 buckets_mask;
- u32 timeout;
- kp_hash_bucket_t buckets[];
-} kp_hash_t;
-
-#define kp_hash_nbuckets(h) (((h)->buckets_mask) + 1)
-#define kp_hash_size(h) ((h)->buckets_mask + KPHASH_ENTRY_PER_BUCKET)
-
-#define kp_hash_foreach_bucket(h, bucket) \
- for (bucket = (h)->buckets; \
- bucket < (h)->buckets + kp_hash_nbuckets(h); \
- bucket++)
-
-#define kp_hash_foreach_entry(h, bucket, i) \
- kp_hash_foreach_bucket(h, bucket) \
- for (i = 0; i < KPHASH_ENTRY_PER_BUCKET; i++)
-
-#define kp_hash_foreach_valid_entry(h, bucket, i, now) \
- kp_hash_foreach_entry(h, bucket, i) \
- if (!clib_u32_loop_gt((now), bucket->timeout[i]))
-
-static_always_inline
-kp_hash_t *kp_hash_alloc(u32 buckets, u32 timeout)
-{
- if (!is_pow2(buckets))
- return NULL;
-
- // Allocate 1 more bucket for prefetch
- u32 size = ((u64)&((kp_hash_t *)(0))->buckets[0]) +
- sizeof(kp_hash_bucket_t) * (buckets + 1);
- u8 *mem = 0;
- kp_hash_t *h;
- vec_alloc_aligned(mem, size, CLIB_CACHE_LINE_BYTES);
- h = (kp_hash_t *)mem;
- h->buckets_mask = (buckets - 1);
- h->timeout = timeout;
- return h;
-}
-
-static_always_inline
-void kp_hash_free(kp_hash_t *h)
-{
- u8 *mem = (u8 *)h;
- vec_free(mem);
-}
-
-static_always_inline
-u32 kp_hash_hash(u64 k0, u64 k1, u64 k2, u64 k3, u64 k4)
-{
-#ifdef clib_crc32c_uses_intrinsics
- u64 key[5];
- key[0] = k0;
- key[1] = k1;
- key[2] = k2;
- key[3] = k3;
- key[4] = k4;
- return clib_crc32c ((u8 *) key, 40);
-#else
- u64 tmp = k0 ^ k1 ^ k2 ^ k3 ^ k4;
- return (u32)clib_xxhash (tmp);
-#endif
-}
-
-static_always_inline
-void kp_hash_prefetch_bucket(kp_hash_t *ht, u32 hash)
-{
- kp_hash_bucket_t *bucket = &ht->buckets[hash & ht->buckets_mask];
- CLIB_PREFETCH(bucket, sizeof(*bucket), READ);
-}
-
-static_always_inline
-void kp_hash_get(kp_hash_t *ht, u32 hash, u32 vip, u32 time_now,
- u32 *available_index, u32 *found_value)
-{
- kp_hash_bucket_t *bucket = &ht->buckets[hash & ht->buckets_mask];
- *found_value = ~0;
- *available_index = ~0;
-#if __SSE4_2__ && KP_HASH_DO_NOT_USE_SSE_BUCKETS == 0
- u32 bitmask, found_index;
- __m128i mask;
-
- // mask[*] = timeout[*] > now
- mask = _mm_cmpgt_epi32(_mm_loadu_si128 ((__m128i *) bucket->timeout),
- _mm_set1_epi32 (time_now));
- // bitmask[*] = now <= timeout[*/4]
- bitmask = (~_mm_movemask_epi8(mask)) & 0xffff;
- // Get first index with now <= timeout[*], if any.
- *available_index = (bitmask)?__builtin_ctz(bitmask)/4:*available_index;
-
- // mask[*] = (timeout[*] > now) && (hash[*] == hash)
- mask = _mm_and_si128(mask,
- _mm_cmpeq_epi32(
- _mm_loadu_si128 ((__m128i *) bucket->hash),
- _mm_set1_epi32 (hash)));
-
- // Load the array of vip values
- // mask[*] = (timeout[*] > now) && (hash[*] == hash) && (vip[*] == vip)
- mask = _mm_and_si128(mask,
- _mm_cmpeq_epi32(
- _mm_loadu_si128 ((__m128i *) bucket->vip),
- _mm_set1_epi32 (vip)));
-
- // mask[*] = (timeout[*x4] > now) && (hash[*x4] == hash) && (vip[*x4] == vip)
- bitmask = _mm_movemask_epi8(mask);
- // Get first index, if any
- found_index = (bitmask)?__builtin_ctzll(bitmask)/4:0;
- ASSERT(found_index < 4);
- *found_value = (bitmask)?bucket->value[found_index]:*found_value;
- bucket->timeout[found_index] =
- (bitmask)?time_now + ht->timeout:bucket->timeout[found_index];
-#else
- u32 i;
- for (i = 0; i < KPHASH_ENTRY_PER_BUCKET; i++) {
- u8 cmp = (bucket->hash[i] == hash && bucket->vip[i] == vip);
- u8 timeouted = clib_u32_loop_gt(time_now, bucket->timeout[i]);
- *found_value = (cmp || timeouted)?*found_value:bucket->value[i];
- bucket->timeout[i] = (cmp || timeouted)?time_now + ht->timeout:bucket->timeout[i];
- *available_index = (timeouted && (*available_index == ~0))?i:*available_index;
-
- if (!cmp)
- return;
- }
-#endif
-}
-
-static_always_inline
-u32 kp_hash_available_value(kp_hash_t *h, u32 hash, u32 available_index)
-{
- return h->buckets[hash & h->buckets_mask].value[available_index];
-}
-
-static_always_inline
-void kp_hash_put(kp_hash_t *h, u32 hash, u32 value, u32 vip,
- u32 available_index, u32 time_now)
-{
- kp_hash_bucket_t *bucket = &h->buckets[hash & h->buckets_mask];
- bucket->hash[available_index] = hash;
- bucket->value[available_index] = value;
- bucket->timeout[available_index] = time_now + h->timeout;
- bucket->vip[available_index] = vip;
-}
-
-static_always_inline
-u32 kp_hash_elts(kp_hash_t *h, u32 time_now)
-{
- u32 tot = 0;
- kp_hash_bucket_t *bucket;
- u32 i;
- kp_hash_foreach_valid_entry(h, bucket, i, time_now) {
- tot++;
- }
- return tot;
-}
-
-#endif /* KP_PLUGIN_KP_KPHASH_H_ */
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