xref: /dpdk/lib/table/rte_lru_x86.h (revision 719834a6849e1daf4a70ff7742bbcc3ae7e25607)
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 #include <stdint.h>
9 
10 #include <rte_config.h>
11 #include <rte_common.h>
12 
13 #ifndef RTE_TABLE_HASH_LRU_STRATEGY
14 #define RTE_TABLE_HASH_LRU_STRATEGY                        2
15 #endif
16 
17 #if RTE_TABLE_HASH_LRU_STRATEGY == 2
18 
19 #if RTE_CC_IS_GNU
20 #include <x86intrin.h>
21 #else
22 #include <emmintrin.h>
23 #include <smmintrin.h>
24 #include <xmmintrin.h>
25 #endif
26 
27 #define lru_init(bucket)						\
28 	{ bucket->lru_list = 0x0000000100020003LLU; }
29 
30 #define lru_pos(bucket) (bucket->lru_list & 0xFFFFLLU)
31 
32 #define lru_update(bucket, mru_val)					\
33 do {									\
34 	/* set up the masks for all possible shuffles, depends on pos */\
35 	static uint64_t masks[10] = {					\
36 		/* Shuffle order; Make Zero (see _mm_shuffle_epi8 manual) */\
37 		0x0100070605040302, 0x8080808080808080,			\
38 		0x0302070605040100, 0x8080808080808080,			\
39 		0x0504070603020100, 0x8080808080808080,			\
40 		0x0706050403020100, 0x8080808080808080,			\
41 		0x0706050403020100, 0x8080808080808080};		\
42 	/* load up one register with repeats of mru-val  */		\
43 	uint64_t mru2 = mru_val;					\
44 	uint64_t mru3 = mru2 | (mru2 << 16);				\
45 	uint64_t lru = bucket->lru_list;				\
46 	/* XOR to cause the word we're looking for to go to zero */	\
47 	uint64_t mru = lru ^ ((mru3 << 32) | mru3);			\
48 	__m128i c = _mm_cvtsi64_si128(mru);				\
49 	__m128i b = _mm_cvtsi64_si128(lru);				\
50 	/* Find the minimum value (first zero word, if it's in there) */\
51 	__m128i d = _mm_minpos_epu16(c);				\
52 	/* Second word is the index to found word (first word is the value) */\
53 	unsigned int pos = _mm_extract_epi16(d, 1);			\
54 	/* move the recently used location to top of list */		\
55 	__m128i k = _mm_shuffle_epi8(b, *((__m128i *) &masks[2 * pos]));\
56 	/* Finally, update the original list with the reordered data */	\
57 	bucket->lru_list = _mm_extract_epi64(k, 0);			\
58 	/* Phwew! */							\
59 } while (0)
60 
61 #elif RTE_TABLE_HASH_LRU_STRATEGY == 3
62 
63 #if RTE_CC_IS_GNU
64 #include <x86intrin.h>
65 #else
66 #include <emmintrin.h>
67 #include <smmintrin.h>
68 #include <xmmintrin.h>
69 #endif
70 
71 #define lru_init(bucket)						\
72 	{ bucket->lru_list = ~0LLU; }
73 
74 static inline int
75 f_lru_pos(uint64_t lru_list)
76 {
77 	__m128i lst = _mm_set_epi64x((uint64_t)-1, lru_list);
78 	__m128i min = _mm_minpos_epu16(lst);
79 	return _mm_extract_epi16(min, 1);
80 }
81 #define lru_pos(bucket) f_lru_pos(bucket->lru_list)
82 
83 #define lru_update(bucket, mru_val)					\
84 do {									\
85 	const uint64_t orvals[] = {0xFFFFLLU, 0xFFFFLLU << 16,		\
86 		0xFFFFLLU << 32, 0xFFFFLLU << 48, 0LLU};		\
87 	const uint64_t decs[] = {0x1000100010001LLU, 0};		\
88 	__m128i lru = _mm_cvtsi64_si128(bucket->lru_list);		\
89 	__m128i vdec = _mm_cvtsi64_si128(decs[mru_val>>2]);		\
90 	lru = _mm_subs_epu16(lru, vdec);				\
91 	bucket->lru_list = _mm_extract_epi64(lru, 0) | orvals[mru_val];	\
92 } while (0)
93 
94 #endif
95 
96 #endif
97