1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* Test for find_*_bit functions.
*
* Copyright (c) 2017 Cavium.
*/
/*
* find_bit functions are widely used in kernel, so the successful boot
* is good enough test for correctness.
*
* This test is focused on performance of traversing bitmaps. Two typical
* scenarios are reproduced:
* - randomly filled bitmap with approximately equal number of set and
* cleared bits;
* - sparse bitmap with few set bits at random positions.
*/
#include <linux/bitops.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/printk.h>
#include <linux/random.h>
#define BITMAP_LEN (4096UL * 8 * 10)
#define SPARSE 500
static DECLARE_BITMAP(bitmap, BITMAP_LEN) __initdata;
static DECLARE_BITMAP(bitmap2, BITMAP_LEN) __initdata;
/*
* This is Schlemiel the Painter's algorithm. It should be called after
* all other tests for the same bitmap because it sets all bits of bitmap to 1.
*/
static int __init test_find_first_bit(void *bitmap, unsigned long len)
{
unsigned long i, cnt;
ktime_t time;
time = ktime_get();
for (cnt = i = 0; i < len; cnt++) {
i = find_first_bit(bitmap, len);
__clear_bit(i, bitmap);
}
time = ktime_get() - time;
pr_err("find_first_bit: %18llu ns, %6ld iterations\n", time, cnt);
return 0;
}
static int __init test_find_first_and_bit(void *bitmap, const void *bitmap2, unsigned long len)
{
static DECLARE_BITMAP(cp, BITMAP_LEN) __initdata;
unsigned long i, cnt;
ktime_t time;
bitmap_copy(cp, bitmap, BITMAP_LEN);
time = ktime_get();
for (cnt = i = 0; i < len; cnt++) {
i = find_first_and_bit(cp, bitmap2, len);
__clear_bit(i, cp);
}
time = ktime_get() - time;
pr_err("find_first_and_bit: %18llu ns, %6ld iterations\n", time, cnt);
return 0;
}
static int __init test_find_next_bit(const void *bitmap, unsigned long len)
{
unsigned long i, cnt;
ktime_t time;
time = ktime_get();
for (cnt = i = 0; i < BITMAP_LEN; cnt++)
i = find_next_bit(bitmap, BITMAP_LEN, i) + 1;
time = ktime_get() - time;
pr_err("find_next_bit: %18llu ns, %6ld iterations\n", time, cnt);
return 0;
}
static int __init test_find_next_zero_bit(const void *bitmap, unsigned long len)
{
unsigned long i, cnt;
ktime_t time;
time = ktime_get();
for (cnt = i = 0; i < BITMAP_LEN; cnt++)
i = find_next_zero_bit(bitmap, len, i) + 1;
time = ktime_get() - time;
pr_err("find_next_zero_bit: %18llu ns, %6ld iterations\n", time, cnt);
return 0;
}
static int __init test_find_last_bit(const void *bitmap, unsigned long len)
{
unsigned long l, cnt = 0;
ktime_t time;
time = ktime_get();
do {
cnt++;
l = find_last_bit(bitmap, len);
if (l >= len)
break;
len = l;
} while (len);
time = ktime_get() - time;
pr_err("find_last_bit: %18llu ns, %6ld iterations\n", time, cnt);
return 0;
}
static int __init test_find_next_and_bit(const void *bitmap,
const void *bitmap2, unsigned long len)
{
unsigned long i, cnt;
ktime_t time;
time = ktime_get();
for (cnt = i = 0; i < BITMAP_LEN; cnt++)
i = find_next_and_bit(bitmap, bitmap2, BITMAP_LEN, i + 1);
time = ktime_get() - time;
pr_err("find_next_and_bit: %18llu ns, %6ld iterations\n", time, cnt);
return 0;
}
static int __init find_bit_test(void)
{
unsigned long nbits = BITMAP_LEN / SPARSE;
pr_err("\nStart testing find_bit() with random-filled bitmap\n");
get_random_bytes(bitmap, sizeof(bitmap));
get_random_bytes(bitmap2, sizeof(bitmap2));
test_find_next_bit(bitmap, BITMAP_LEN);
test_find_next_zero_bit(bitmap, BITMAP_LEN);
test_find_last_bit(bitmap, BITMAP_LEN);
/*
* test_find_first_bit() may take some time, so
* traverse only part of bitmap to avoid soft lockup.
*/
test_find_first_bit(bitmap, BITMAP_LEN / 10);
test_find_first_and_bit(bitmap, bitmap2, BITMAP_LEN / 2);
test_find_next_and_bit(bitmap, bitmap2, BITMAP_LEN);
pr_err("\nStart testing find_bit() with sparse bitmap\n");
bitmap_zero(bitmap, BITMAP_LEN);
bitmap_zero(bitmap2, BITMAP_LEN);
while (nbits--) {
__set_bit(prandom_u32() % BITMAP_LEN, bitmap);
__set_bit(prandom_u32() % BITMAP_LEN, bitmap2);
}
test_find_next_bit(bitmap, BITMAP_LEN);
test_find_next_zero_bit(bitmap, BITMAP_LEN);
test_find_last_bit(bitmap, BITMAP_LEN);
test_find_first_bit(bitmap, BITMAP_LEN);
test_find_first_and_bit(bitmap, bitmap2, BITMAP_LEN);
test_find_next_and_bit(bitmap, bitmap2, BITMAP_LEN);
/*
* Everything is OK. Return error just to let user run benchmark
* again without annoying rmmod.
*/
return -EINVAL;
}
module_init(find_bit_test);
MODULE_LICENSE("GPL");
|
