1 // SPDX-License-Identifier: GPL-2.0 1 // SPDX-License-Identifier: GPL-2.0
2 /* 2 /*
3 * fill_buf benchmark 3 * fill_buf benchmark
4 * 4 *
5 * Copyright (C) 2018 Intel Corporation 5 * Copyright (C) 2018 Intel Corporation
6 * 6 *
7 * Authors: 7 * Authors:
8 * Sai Praneeth Prakhya <sai.praneeth.prakh 8 * Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>,
9 * Fenghua Yu <fenghua.yu@intel.com> 9 * Fenghua Yu <fenghua.yu@intel.com>
10 */ 10 */
11 #include <stdio.h> 11 #include <stdio.h>
12 #include <unistd.h> 12 #include <unistd.h>
13 #include <stdlib.h> 13 #include <stdlib.h>
14 #include <sys/types.h> 14 #include <sys/types.h>
15 #include <sys/wait.h> 15 #include <sys/wait.h>
16 #include <inttypes.h> 16 #include <inttypes.h>
17 #include <string.h> 17 #include <string.h>
18 18
19 #include "resctrl.h" 19 #include "resctrl.h"
20 20
21 #define CL_SIZE (64) 21 #define CL_SIZE (64)
22 #define PAGE_SIZE (4 * 1024) 22 #define PAGE_SIZE (4 * 1024)
23 #define MB (1024 * 1024) 23 #define MB (1024 * 1024)
24 24
25 static void sb(void) 25 static void sb(void)
26 { 26 {
27 #if defined(__i386) || defined(__x86_64) 27 #if defined(__i386) || defined(__x86_64)
28 asm volatile("sfence\n\t" 28 asm volatile("sfence\n\t"
29 : : : "memory"); 29 : : : "memory");
30 #endif 30 #endif
31 } 31 }
32 32
33 static void cl_flush(void *p) 33 static void cl_flush(void *p)
34 { 34 {
35 #if defined(__i386) || defined(__x86_64) 35 #if defined(__i386) || defined(__x86_64)
36 asm volatile("clflush (%0)\n\t" 36 asm volatile("clflush (%0)\n\t"
37 : : "r"(p) : "memory"); 37 : : "r"(p) : "memory");
38 #endif 38 #endif
39 } 39 }
40 40
41 void mem_flush(unsigned char *buf, size_t buf_ 41 void mem_flush(unsigned char *buf, size_t buf_size)
42 { 42 {
43 unsigned char *cp = buf; 43 unsigned char *cp = buf;
44 size_t i = 0; 44 size_t i = 0;
45 45
46 buf_size = buf_size / CL_SIZE; /* mem 46 buf_size = buf_size / CL_SIZE; /* mem size in cache lines */
47 47
48 for (i = 0; i < buf_size; i++) 48 for (i = 0; i < buf_size; i++)
49 cl_flush(&cp[i * CL_SIZE]); 49 cl_flush(&cp[i * CL_SIZE]);
50 50
51 sb(); 51 sb();
52 } 52 }
53 53
54 /* 54 /*
55 * Buffer index step advance to workaround HW 55 * Buffer index step advance to workaround HW prefetching interfering with
56 * the measurements. 56 * the measurements.
57 * 57 *
58 * Must be a prime to step through all indexes 58 * Must be a prime to step through all indexes of the buffer.
59 * 59 *
60 * Some primes work better than others on some 60 * Some primes work better than others on some architectures (from MBA/MBM
61 * result stability point of view). 61 * result stability point of view).
62 */ 62 */
63 #define FILL_IDX_MULT 23 63 #define FILL_IDX_MULT 23
64 64
65 static int fill_one_span_read(unsigned char *b 65 static int fill_one_span_read(unsigned char *buf, size_t buf_size)
66 { 66 {
67 unsigned int size = buf_size / (CL_SIZ 67 unsigned int size = buf_size / (CL_SIZE / 2);
68 unsigned int i, idx = 0; 68 unsigned int i, idx = 0;
69 unsigned char sum = 0; 69 unsigned char sum = 0;
70 70
71 /* 71 /*
72 * Read the buffer in an order that is 72 * Read the buffer in an order that is unexpected by HW prefetching
73 * optimizations to prevent them inter 73 * optimizations to prevent them interfering with the caching pattern.
74 * 74 *
75 * The read order is (in terms of halv 75 * The read order is (in terms of halves of cachelines):
76 * i * FILL_IDX_MULT % size 76 * i * FILL_IDX_MULT % size
77 * The formula is open-coded below to 77 * The formula is open-coded below to avoiding modulo inside the loop
78 * as it improves MBA/MBM result stabi 78 * as it improves MBA/MBM result stability on some architectures.
79 */ 79 */
80 for (i = 0; i < size; i++) { 80 for (i = 0; i < size; i++) {
81 sum += buf[idx * (CL_SIZE / 2) 81 sum += buf[idx * (CL_SIZE / 2)];
82 82
83 idx += FILL_IDX_MULT; 83 idx += FILL_IDX_MULT;
84 while (idx >= size) 84 while (idx >= size)
85 idx -= size; 85 idx -= size;
86 } 86 }
87 87
88 return sum; 88 return sum;
89 } 89 }
90 90
91 static void fill_one_span_write(unsigned char 91 static void fill_one_span_write(unsigned char *buf, size_t buf_size)
92 { 92 {
93 unsigned char *end_ptr = buf + buf_siz 93 unsigned char *end_ptr = buf + buf_size;
94 unsigned char *p; 94 unsigned char *p;
95 95
96 p = buf; 96 p = buf;
97 while (p < end_ptr) { 97 while (p < end_ptr) {
98 *p = '1'; 98 *p = '1';
99 p += (CL_SIZE / 2); 99 p += (CL_SIZE / 2);
100 } 100 }
101 } 101 }
102 102
103 void fill_cache_read(unsigned char *buf, size_ 103 void fill_cache_read(unsigned char *buf, size_t buf_size, bool once)
104 { 104 {
105 int ret = 0; 105 int ret = 0;
106 106
107 while (1) { 107 while (1) {
108 ret = fill_one_span_read(buf, 108 ret = fill_one_span_read(buf, buf_size);
109 if (once) 109 if (once)
110 break; 110 break;
111 } 111 }
112 112
113 /* Consume read result so that reading 113 /* Consume read result so that reading memory is not optimized out. */
114 *value_sink = ret; 114 *value_sink = ret;
115 } 115 }
116 116
117 static void fill_cache_write(unsigned char *bu 117 static void fill_cache_write(unsigned char *buf, size_t buf_size, bool once)
118 { 118 {
119 while (1) { 119 while (1) {
120 fill_one_span_write(buf, buf_s 120 fill_one_span_write(buf, buf_size);
121 if (once) 121 if (once)
122 break; 122 break;
123 } 123 }
124 } 124 }
125 125
126 unsigned char *alloc_buffer(size_t buf_size, i 126 unsigned char *alloc_buffer(size_t buf_size, int memflush)
127 { 127 {
128 void *buf = NULL; 128 void *buf = NULL;
129 uint64_t *p64; 129 uint64_t *p64;
130 size_t s64; 130 size_t s64;
131 int ret; 131 int ret;
132 132
133 ret = posix_memalign(&buf, PAGE_SIZE, 133 ret = posix_memalign(&buf, PAGE_SIZE, buf_size);
134 if (ret < 0) 134 if (ret < 0)
135 return NULL; 135 return NULL;
136 136
137 /* Initialize the buffer */ 137 /* Initialize the buffer */
138 p64 = buf; 138 p64 = buf;
139 s64 = buf_size / sizeof(uint64_t); 139 s64 = buf_size / sizeof(uint64_t);
140 140
141 while (s64 > 0) { 141 while (s64 > 0) {
142 *p64 = (uint64_t)rand(); 142 *p64 = (uint64_t)rand();
143 p64 += (CL_SIZE / sizeof(uint6 143 p64 += (CL_SIZE / sizeof(uint64_t));
144 s64 -= (CL_SIZE / sizeof(uint6 144 s64 -= (CL_SIZE / sizeof(uint64_t));
145 } 145 }
146 146
147 /* Flush the memory before using to av 147 /* Flush the memory before using to avoid "cache hot pages" effect */
148 if (memflush) 148 if (memflush)
149 mem_flush(buf, buf_size); 149 mem_flush(buf, buf_size);
150 150
151 return buf; 151 return buf;
152 } 152 }
153 153
154 int run_fill_buf(size_t buf_size, int memflush 154 int run_fill_buf(size_t buf_size, int memflush, int op, bool once)
155 { 155 {
156 unsigned char *buf; 156 unsigned char *buf;
157 157
158 buf = alloc_buffer(buf_size, memflush) 158 buf = alloc_buffer(buf_size, memflush);
159 if (!buf) 159 if (!buf)
160 return -1; 160 return -1;
161 161
162 if (op == 0) 162 if (op == 0)
163 fill_cache_read(buf, buf_size, 163 fill_cache_read(buf, buf_size, once);
164 else 164 else
165 fill_cache_write(buf, buf_size 165 fill_cache_write(buf, buf_size, once);
166 free(buf); 166 free(buf);
167 167
168 return 0; 168 return 0;
169 } 169 }
170 170
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