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18
19#define BH_TRACE 0
20#include <linux/module.h>
21#include <linux/raid/xor.h>
22#include <linux/jiffies.h>
23#include <asm/xor.h>
24
25
26static struct xor_block_template *active_template;
27
28void
29xor_blocks(unsigned int src_count, unsigned int bytes, void *dest, void **srcs)
30{
31 unsigned long *p1, *p2, *p3, *p4;
32
33 p1 = (unsigned long *) srcs[0];
34 if (src_count == 1) {
35 active_template->do_2(bytes, dest, p1);
36 return;
37 }
38
39 p2 = (unsigned long *) srcs[1];
40 if (src_count == 2) {
41 active_template->do_3(bytes, dest, p1, p2);
42 return;
43 }
44
45 p3 = (unsigned long *) srcs[2];
46 if (src_count == 3) {
47 active_template->do_4(bytes, dest, p1, p2, p3);
48 return;
49 }
50
51 p4 = (unsigned long *) srcs[3];
52 active_template->do_5(bytes, dest, p1, p2, p3, p4);
53}
54EXPORT_SYMBOL(xor_blocks);
55
56
57static struct xor_block_template *template_list;
58
59#define BENCH_SIZE (PAGE_SIZE)
60
61static void
62do_xor_speed(struct xor_block_template *tmpl, void *b1, void *b2)
63{
64 int speed;
65 unsigned long now;
66 int i, count, max;
67
68 tmpl->next = template_list;
69 template_list = tmpl;
70
71
72
73
74
75
76 max = 0;
77 for (i = 0; i < 5; i++) {
78 now = jiffies;
79 count = 0;
80 while (jiffies == now) {
81 mb();
82 tmpl->do_2(BENCH_SIZE, b1, b2);
83 mb();
84 count++;
85 mb();
86 }
87 if (count > max)
88 max = count;
89 }
90
91 speed = max * (HZ * BENCH_SIZE / 1024);
92 tmpl->speed = speed;
93
94 printk(KERN_INFO " %-10s: %5d.%03d MB/sec\n", tmpl->name,
95 speed / 1000, speed % 1000);
96}
97
98static int __init
99calibrate_xor_blocks(void)
100{
101 void *b1, *b2;
102 struct xor_block_template *f, *fastest;
103
104
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108
109 b1 = (void *) __get_free_pages(GFP_KERNEL | __GFP_NOTRACK, 2);
110 if (!b1) {
111 printk(KERN_WARNING "xor: Yikes! No memory available.\n");
112 return -ENOMEM;
113 }
114 b2 = b1 + 2*PAGE_SIZE + BENCH_SIZE;
115
116
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120
121 fastest = NULL;
122
123#ifdef XOR_SELECT_TEMPLATE
124 fastest = XOR_SELECT_TEMPLATE(fastest);
125#endif
126
127#define xor_speed(templ) do_xor_speed((templ), b1, b2)
128
129 if (fastest) {
130 printk(KERN_INFO "xor: automatically using best "
131 "checksumming function: %s\n",
132 fastest->name);
133 xor_speed(fastest);
134 } else {
135 printk(KERN_INFO "xor: measuring software checksum speed\n");
136 XOR_TRY_TEMPLATES;
137 fastest = template_list;
138 for (f = fastest; f; f = f->next)
139 if (f->speed > fastest->speed)
140 fastest = f;
141 }
142
143 printk(KERN_INFO "xor: using function: %s (%d.%03d MB/sec)\n",
144 fastest->name, fastest->speed / 1000, fastest->speed % 1000);
145
146#undef xor_speed
147
148 free_pages((unsigned long)b1, 2);
149
150 active_template = fastest;
151 return 0;
152}
153
154static __exit void xor_exit(void) { }
155
156MODULE_LICENSE("GPL");
157
158
159core_initcall(calibrate_xor_blocks);
160module_exit(xor_exit);
161