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Diffstat (limited to 'src/plugins/kubeproxy/kphash.h')
| -rw-r--r-- | src/plugins/kubeproxy/kphash.h | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/src/plugins/kubeproxy/kphash.h b/src/plugins/kubeproxy/kphash.h new file mode 100644 index 00000000000..2957aeb2a53 --- /dev/null +++ b/src/plugins/kubeproxy/kphash.h @@ -0,0 +1,216 @@ +/* + * 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_ */ |