DPDK  16.11.11
rte_lru.h
1 /*-
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33 
34 #ifndef __INCLUDE_RTE_LRU_H__
35 #define __INCLUDE_RTE_LRU_H__
36 
37 #ifdef __cplusplus
38 extern "C" {
39 #endif
40 
41 #include <stdint.h>
42 
43 #ifdef __INTEL_COMPILER
44 #define GCC_VERSION (0)
45 #else
46 #define GCC_VERSION (__GNUC__ * 10000+__GNUC_MINOR__*100 + __GNUC_PATCHLEVEL__)
47 #endif
48 
49 #ifndef RTE_TABLE_HASH_LRU_STRATEGY
50 #ifdef __SSE4_2__
51 #define RTE_TABLE_HASH_LRU_STRATEGY 2
52 #else /* if no SSE, use simple scalar version */
53 #define RTE_TABLE_HASH_LRU_STRATEGY 1
54 #endif
55 #endif
56 
57 #ifndef RTE_ARCH_X86_64
58 #undef RTE_TABLE_HASH_LRU_STRATEGY
59 #define RTE_TABLE_HASH_LRU_STRATEGY 1
60 #endif
61 
62 #if (RTE_TABLE_HASH_LRU_STRATEGY < 0) || (RTE_TABLE_HASH_LRU_STRATEGY > 3)
63 #error Invalid value for RTE_TABLE_HASH_LRU_STRATEGY
64 #endif
65 
66 #if RTE_TABLE_HASH_LRU_STRATEGY == 0
67 
68 #define lru_init(bucket) \
69 do \
70  bucket = bucket; \
71 while (0)
72 
73 #define lru_pos(bucket) (bucket->lru_list & 0xFFFFLLU)
74 
75 #define lru_update(bucket, mru_val) \
76 do { \
77  bucket = bucket; \
78  mru_val = mru_val; \
79 } while (0)
80 
81 #elif RTE_TABLE_HASH_LRU_STRATEGY == 1
82 
83 #define lru_init(bucket) \
84 do \
85  bucket->lru_list = 0x0000000100020003LLU; \
86 while (0)
87 
88 #define lru_pos(bucket) (bucket->lru_list & 0xFFFFLLU)
89 
90 #define lru_update(bucket, mru_val) \
91 do { \
92  uint64_t x, pos, x0, x1, x2, mask; \
93  \
94  x = bucket->lru_list; \
95  \
96  pos = 4; \
97  if ((x >> 48) == ((uint64_t) mru_val)) \
98  pos = 3; \
99  \
100  if (((x >> 32) & 0xFFFFLLU) == ((uint64_t) mru_val)) \
101  pos = 2; \
102  \
103  if (((x >> 16) & 0xFFFFLLU) == ((uint64_t) mru_val)) \
104  pos = 1; \
105  \
106  if ((x & 0xFFFFLLU) == ((uint64_t) mru_val)) \
107  pos = 0; \
108  \
109  \
110  pos <<= 4; \
111  mask = (~0LLU) << pos; \
112  x0 = x & (~mask); \
113  x1 = (x >> 16) & mask; \
114  x2 = (x << (48 - pos)) & (0xFFFFLLU << 48); \
115  x = x0 | x1 | x2; \
116  \
117  if (pos != 64) \
118  bucket->lru_list = x; \
119 } while (0)
120 
121 #elif RTE_TABLE_HASH_LRU_STRATEGY == 2
122 
123 #if GCC_VERSION > 40306
124 #include <x86intrin.h>
125 #else
126 #include <emmintrin.h>
127 #include <smmintrin.h>
128 #include <xmmintrin.h>
129 #endif
130 
131 #define lru_init(bucket) \
132 do \
133  bucket->lru_list = 0x0000000100020003LLU; \
134 while (0)
135 
136 #define lru_pos(bucket) (bucket->lru_list & 0xFFFFLLU)
137 
138 #define lru_update(bucket, mru_val) \
139 do { \
140  /* set up the masks for all possible shuffles, depends on pos */\
141  static uint64_t masks[10] = { \
142  /* Shuffle order; Make Zero (see _mm_shuffle_epi8 manual) */\
143  0x0100070605040302, 0x8080808080808080, \
144  0x0302070605040100, 0x8080808080808080, \
145  0x0504070603020100, 0x8080808080808080, \
146  0x0706050403020100, 0x8080808080808080, \
147  0x0706050403020100, 0x8080808080808080}; \
148  /* load up one register with repeats of mru-val */ \
149  uint64_t mru2 = mru_val; \
150  uint64_t mru3 = mru2 | (mru2 << 16); \
151  uint64_t lru = bucket->lru_list; \
152  /* XOR to cause the word we're looking for to go to zero */ \
153  uint64_t mru = lru ^ ((mru3 << 32) | mru3); \
154  __m128i c = _mm_cvtsi64_si128(mru); \
155  __m128i b = _mm_cvtsi64_si128(lru); \
156  /* Find the minimum value (first zero word, if it's in there) */\
157  __m128i d = _mm_minpos_epu16(c); \
158  /* Second word is the index to found word (first word is the value) */\
159  unsigned pos = _mm_extract_epi16(d, 1); \
160  /* move the recently used location to top of list */ \
161  __m128i k = _mm_shuffle_epi8(b, *((__m128i *) &masks[2 * pos]));\
162  /* Finally, update the original list with the reordered data */ \
163  bucket->lru_list = _mm_extract_epi64(k, 0); \
164  /* Phwew! */ \
165 } while (0)
166 
167 #elif RTE_TABLE_HASH_LRU_STRATEGY == 3
168 
169 #if GCC_VERSION > 40306
170 #include <x86intrin.h>
171 #else
172 #include <emmintrin.h>
173 #include <smmintrin.h>
174 #include <xmmintrin.h>
175 #endif
176 
177 #define lru_init(bucket) \
178 do \
179  bucket->lru_list = ~0LLU; \
180 while (0)
181 
182 
183 static inline int
184 f_lru_pos(uint64_t lru_list)
185 {
186  __m128i lst = _mm_set_epi64x((uint64_t)-1, lru_list);
187  __m128i min = _mm_minpos_epu16(lst);
188  return _mm_extract_epi16(min, 1);
189 }
190 #define lru_pos(bucket) f_lru_pos(bucket->lru_list)
191 
192 #define lru_update(bucket, mru_val) \
193 do { \
194  const uint64_t orvals[] = {0xFFFFLLU, 0xFFFFLLU << 16, \
195  0xFFFFLLU << 32, 0xFFFFLLU << 48, 0LLU}; \
196  const uint64_t decs[] = {0x1000100010001LLU, 0}; \
197  __m128i lru = _mm_cvtsi64_si128(bucket->lru_list); \
198  __m128i vdec = _mm_cvtsi64_si128(decs[mru_val>>2]); \
199  lru = _mm_subs_epu16(lru, vdec); \
200  bucket->lru_list = _mm_extract_epi64(lru, 0) | orvals[mru_val]; \
201 } while (0)
202 
203 #else
204 
205 #error "Incorrect value for RTE_TABLE_HASH_LRU_STRATEGY"
206 
207 #endif
208 
209 #ifdef __cplusplus
210 }
211 #endif
212 
213 #endif
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