DPDK  20.08.0
rte_lru_x86.h
1 /* SPDX-License-Identifier: BSD-3-Clause
2  * Copyright(c) 2010-2014 Intel Corporation
3  */
4 
5 #ifndef __INCLUDE_RTE_LRU_X86_H__
6 #define __INCLUDE_RTE_LRU_X86_H__
7 
8 #ifdef __cplusplus
9 extern "C" {
10 #endif
11 
12 #include <stdint.h>
13 
14 #include <rte_config.h>
15 
16 #ifndef RTE_TABLE_HASH_LRU_STRATEGY
17 #define RTE_TABLE_HASH_LRU_STRATEGY 2
18 #endif
19 
20 #if RTE_TABLE_HASH_LRU_STRATEGY == 2
21 
22 #if RTE_CC_IS_GNU && (GCC_VERSION > 40306)
23 #include <x86intrin.h>
24 #else
25 #include <emmintrin.h>
26 #include <smmintrin.h>
27 #include <xmmintrin.h>
28 #endif
29 
30 #define lru_init(bucket) \
31  { bucket->lru_list = 0x0000000100020003LLU; }
32 
33 #define lru_pos(bucket) (bucket->lru_list & 0xFFFFLLU)
34 
35 #define lru_update(bucket, mru_val) \
36 do { \
37  /* set up the masks for all possible shuffles, depends on pos */\
38  static uint64_t masks[10] = { \
39  /* Shuffle order; Make Zero (see _mm_shuffle_epi8 manual) */\
40  0x0100070605040302, 0x8080808080808080, \
41  0x0302070605040100, 0x8080808080808080, \
42  0x0504070603020100, 0x8080808080808080, \
43  0x0706050403020100, 0x8080808080808080, \
44  0x0706050403020100, 0x8080808080808080}; \
45  /* load up one register with repeats of mru-val */ \
46  uint64_t mru2 = mru_val; \
47  uint64_t mru3 = mru2 | (mru2 << 16); \
48  uint64_t lru = bucket->lru_list; \
49  /* XOR to cause the word we're looking for to go to zero */ \
50  uint64_t mru = lru ^ ((mru3 << 32) | mru3); \
51  __m128i c = _mm_cvtsi64_si128(mru); \
52  __m128i b = _mm_cvtsi64_si128(lru); \
53  /* Find the minimum value (first zero word, if it's in there) */\
54  __m128i d = _mm_minpos_epu16(c); \
55  /* Second word is the index to found word (first word is the value) */\
56  unsigned int pos = _mm_extract_epi16(d, 1); \
57  /* move the recently used location to top of list */ \
58  __m128i k = _mm_shuffle_epi8(b, *((__m128i *) &masks[2 * pos]));\
59  /* Finally, update the original list with the reordered data */ \
60  bucket->lru_list = _mm_extract_epi64(k, 0); \
61  /* Phwew! */ \
62 } while (0)
63 
64 #elif RTE_TABLE_HASH_LRU_STRATEGY == 3
65 
66 #if RTE_CC_IS_GNU && (GCC_VERSION > 40306)
67 #include <x86intrin.h>
68 #else
69 #include <emmintrin.h>
70 #include <smmintrin.h>
71 #include <xmmintrin.h>
72 #endif
73 
74 #define lru_init(bucket) \
75  { bucket->lru_list = ~0LLU; }
76 
77 static inline int
78 f_lru_pos(uint64_t lru_list)
79 {
80  __m128i lst = _mm_set_epi64x((uint64_t)-1, lru_list);
81  __m128i min = _mm_minpos_epu16(lst);
82  return _mm_extract_epi16(min, 1);
83 }
84 #define lru_pos(bucket) f_lru_pos(bucket->lru_list)
85 
86 #define lru_update(bucket, mru_val) \
87 do { \
88  const uint64_t orvals[] = {0xFFFFLLU, 0xFFFFLLU << 16, \
89  0xFFFFLLU << 32, 0xFFFFLLU << 48, 0LLU}; \
90  const uint64_t decs[] = {0x1000100010001LLU, 0}; \
91  __m128i lru = _mm_cvtsi64_si128(bucket->lru_list); \
92  __m128i vdec = _mm_cvtsi64_si128(decs[mru_val>>2]); \
93  lru = _mm_subs_epu16(lru, vdec); \
94  bucket->lru_list = _mm_extract_epi64(lru, 0) | orvals[mru_val]; \
95 } while (0)
96 
97 #endif
98 
99 #ifdef __cplusplus
100 }
101 #endif
102 
103 #endif