aboutsummaryrefslogtreecommitdiffstats
path: root/lib/find_bit_benchmark.c
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2018-02-07 01:15:42 -0500
committerLinus Torvalds <torvalds@linux-foundation.org>2018-02-07 01:15:42 -0500
commita2e5790d841658485d642196dbb0927303d6c22f (patch)
treeb3d28c9bcb7da6880806146fd22a88a7ee7f733e /lib/find_bit_benchmark.c
parentab2d92ad881da11331280aedf612d82e61cb6d41 (diff)
parent60c3e026d73ccabb075fb70ba02f8512ab40cf2c (diff)
Merge branch 'akpm' (patches from Andrew)
Merge misc updates from Andrew Morton: - kasan updates - procfs - lib/bitmap updates - other lib/ updates - checkpatch tweaks - rapidio - ubsan - pipe fixes and cleanups - lots of other misc bits * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (114 commits) Documentation/sysctl/user.txt: fix typo MAINTAINERS: update ARM/QUALCOMM SUPPORT patterns MAINTAINERS: update various PALM patterns MAINTAINERS: update "ARM/OXNAS platform support" patterns MAINTAINERS: update Cortina/Gemini patterns MAINTAINERS: remove ARM/CLKDEV SUPPORT file pattern MAINTAINERS: remove ANDROID ION pattern mm: docs: add blank lines to silence sphinx "Unexpected indentation" errors mm: docs: fix parameter names mismatch mm: docs: fixup punctuation pipe: read buffer limits atomically pipe: simplify round_pipe_size() pipe: reject F_SETPIPE_SZ with size over UINT_MAX pipe: fix off-by-one error when checking buffer limits pipe: actually allow root to exceed the pipe buffer limits pipe, sysctl: remove pipe_proc_fn() pipe, sysctl: drop 'min' parameter from pipe-max-size converter kasan: rework Kconfig settings crash_dump: is_kdump_kernel can be boolean kernel/mutex: mutex_is_locked can be boolean ...
Diffstat (limited to 'lib/find_bit_benchmark.c')
-rw-r--r--lib/find_bit_benchmark.c162
1 files changed, 162 insertions, 0 deletions
diff --git a/lib/find_bit_benchmark.c b/lib/find_bit_benchmark.c
new file mode 100644
index 000000000000..5985a25e6cbc
--- /dev/null
+++ b/lib/find_bit_benchmark.c
@@ -0,0 +1,162 @@
1/*
2 * Test for find_*_bit functions.
3 *
4 * Copyright (c) 2017 Cavium.
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of version 2 of the GNU General Public
8 * License as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
14 */
15
16/*
17 * find_bit functions are widely used in kernel, so the successful boot
18 * is good enough test for correctness.
19 *
20 * This test is focused on performance of traversing bitmaps. Two typical
21 * scenarios are reproduced:
22 * - randomly filled bitmap with approximately equal number of set and
23 * cleared bits;
24 * - sparse bitmap with few set bits at random positions.
25 */
26
27#include <linux/bitops.h>
28#include <linux/kernel.h>
29#include <linux/list.h>
30#include <linux/module.h>
31#include <linux/printk.h>
32#include <linux/random.h>
33
34#define BITMAP_LEN (4096UL * 8 * 10)
35#define SPARSE 500
36
37static DECLARE_BITMAP(bitmap, BITMAP_LEN) __initdata;
38static DECLARE_BITMAP(bitmap2, BITMAP_LEN) __initdata;
39
40/*
41 * This is Schlemiel the Painter's algorithm. It should be called after
42 * all other tests for the same bitmap because it sets all bits of bitmap to 1.
43 */
44static int __init test_find_first_bit(void *bitmap, unsigned long len)
45{
46 unsigned long i, cnt;
47 ktime_t time;
48
49 time = ktime_get();
50 for (cnt = i = 0; i < len; cnt++) {
51 i = find_first_bit(bitmap, len);
52 __clear_bit(i, bitmap);
53 }
54 time = ktime_get() - time;
55 pr_err("find_first_bit: %18llu ns, %6ld iterations\n", time, cnt);
56
57 return 0;
58}
59
60static int __init test_find_next_bit(const void *bitmap, unsigned long len)
61{
62 unsigned long i, cnt;
63 ktime_t time;
64
65 time = ktime_get();
66 for (cnt = i = 0; i < BITMAP_LEN; cnt++)
67 i = find_next_bit(bitmap, BITMAP_LEN, i) + 1;
68 time = ktime_get() - time;
69 pr_err("find_next_bit: %18llu ns, %6ld iterations\n", time, cnt);
70
71 return 0;
72}
73
74static int __init test_find_next_zero_bit(const void *bitmap, unsigned long len)
75{
76 unsigned long i, cnt;
77 ktime_t time;
78
79 time = ktime_get();
80 for (cnt = i = 0; i < BITMAP_LEN; cnt++)
81 i = find_next_zero_bit(bitmap, len, i) + 1;
82 time = ktime_get() - time;
83 pr_err("find_next_zero_bit: %18llu ns, %6ld iterations\n", time, cnt);
84
85 return 0;
86}
87
88static int __init test_find_last_bit(const void *bitmap, unsigned long len)
89{
90 unsigned long l, cnt = 0;
91 ktime_t time;
92
93 time = ktime_get();
94 do {
95 cnt++;
96 l = find_last_bit(bitmap, len);
97 if (l >= len)
98 break;
99 len = l;
100 } while (len);
101 time = ktime_get() - time;
102 pr_err("find_last_bit: %18llu ns, %6ld iterations\n", time, cnt);
103
104 return 0;
105}
106
107static int __init test_find_next_and_bit(const void *bitmap,
108 const void *bitmap2, unsigned long len)
109{
110 unsigned long i, cnt;
111 cycles_t cycles;
112
113 cycles = get_cycles();
114 for (cnt = i = 0; i < BITMAP_LEN; cnt++)
115 i = find_next_and_bit(bitmap, bitmap2, BITMAP_LEN, i+1);
116 cycles = get_cycles() - cycles;
117 pr_err("find_next_and_bit:\t\t%llu cycles, %ld iterations\n",
118 (u64)cycles, cnt);
119
120 return 0;
121}
122
123static int __init find_bit_test(void)
124{
125 unsigned long nbits = BITMAP_LEN / SPARSE;
126
127 pr_err("\nStart testing find_bit() with random-filled bitmap\n");
128
129 get_random_bytes(bitmap, sizeof(bitmap));
130 get_random_bytes(bitmap2, sizeof(bitmap2));
131
132 test_find_next_bit(bitmap, BITMAP_LEN);
133 test_find_next_zero_bit(bitmap, BITMAP_LEN);
134 test_find_last_bit(bitmap, BITMAP_LEN);
135 test_find_first_bit(bitmap, BITMAP_LEN);
136 test_find_next_and_bit(bitmap, bitmap2, BITMAP_LEN);
137
138 pr_err("\nStart testing find_bit() with sparse bitmap\n");
139
140 bitmap_zero(bitmap, BITMAP_LEN);
141 bitmap_zero(bitmap2, BITMAP_LEN);
142
143 while (nbits--) {
144 __set_bit(prandom_u32() % BITMAP_LEN, bitmap);
145 __set_bit(prandom_u32() % BITMAP_LEN, bitmap2);
146 }
147
148 test_find_next_bit(bitmap, BITMAP_LEN);
149 test_find_next_zero_bit(bitmap, BITMAP_LEN);
150 test_find_last_bit(bitmap, BITMAP_LEN);
151 test_find_first_bit(bitmap, BITMAP_LEN);
152 test_find_next_and_bit(bitmap, bitmap2, BITMAP_LEN);
153
154 /*
155 * Everything is OK. Return error just to let user run benchmark
156 * again without annoying rmmod.
157 */
158 return -EINVAL;
159}
160module_init(find_bit_test);
161
162MODULE_LICENSE("GPL");