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| 1 | /* |
| 2 | * xor.c : Multiple Devices driver for Linux |
| 3 | * |
| 4 | * Copyright (C) 1996, 1997, 1998, 1999, 2000, |
| 5 | * Ingo Molnar, Matti Aarnio, Jakub Jelinek, Richard Henderson. |
| 6 | * |
| 7 | * Dispatch optimized RAID-5 checksumming functions. |
| 8 | * |
| 9 | * This program is free software; you can redistribute it and/or modify |
| 10 | * it under the terms of the GNU General Public License as published by |
| 11 | * the Free Software Foundation; either version 2, or (at your option) |
| 12 | * any later version. |
| 13 | * |
| 14 | * You should have received a copy of the GNU General Public License |
| 15 | * (for example /usr/src/linux/COPYING); if not, write to the Free |
| 16 | * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| 17 | */ |
| 18 | |
| 19 | #define BH_TRACE 0 |
| 20 | #include <linux/module.h> |
| 21 | #include <linux/gfp.h> |
| 22 | #include <linux/raid/xor.h> |
| 23 | #include <linux/jiffies.h> |
| 24 | #include <asm/xor.h> |
| 25 | |
| 26 | /* The xor routines to use. */ |
| 27 | static struct xor_block_template *active_template; |
| 28 | |
| 29 | void |
| 30 | xor_blocks(unsigned int src_count, unsigned int bytes, void *dest, void **srcs) |
| 31 | { |
| 32 | unsigned long *p1, *p2, *p3, *p4; |
| 33 | |
| 34 | p1 = (unsigned long *) srcs[0]; |
| 35 | if (src_count == 1) { |
| 36 | active_template->do_2(bytes, dest, p1); |
| 37 | return; |
| 38 | } |
| 39 | |
| 40 | p2 = (unsigned long *) srcs[1]; |
| 41 | if (src_count == 2) { |
| 42 | active_template->do_3(bytes, dest, p1, p2); |
| 43 | return; |
| 44 | } |
| 45 | |
| 46 | p3 = (unsigned long *) srcs[2]; |
| 47 | if (src_count == 3) { |
| 48 | active_template->do_4(bytes, dest, p1, p2, p3); |
| 49 | return; |
| 50 | } |
| 51 | |
| 52 | p4 = (unsigned long *) srcs[3]; |
| 53 | active_template->do_5(bytes, dest, p1, p2, p3, p4); |
| 54 | } |
| 55 | EXPORT_SYMBOL(xor_blocks); |
| 56 | |
| 57 | /* Set of all registered templates. */ |
| 58 | static struct xor_block_template *template_list; |
| 59 | |
| 60 | #define BENCH_SIZE (PAGE_SIZE) |
| 61 | |
| 62 | static void |
| 63 | do_xor_speed(struct xor_block_template *tmpl, void *b1, void *b2) |
| 64 | { |
| 65 | int speed; |
| 66 | unsigned long now; |
| 67 | int i, count, max; |
| 68 | |
| 69 | tmpl->next = template_list; |
| 70 | template_list = tmpl; |
| 71 | |
| 72 | /* |
| 73 | * Count the number of XORs done during a whole jiffy, and use |
| 74 | * this to calculate the speed of checksumming. We use a 2-page |
| 75 | * allocation to have guaranteed color L1-cache layout. |
| 76 | */ |
| 77 | max = 0; |
| 78 | for (i = 0; i < 5; i++) { |
| 79 | now = jiffies; |
| 80 | count = 0; |
| 81 | while (jiffies == now) { |
| 82 | mb(); /* prevent loop optimzation */ |
| 83 | tmpl->do_2(BENCH_SIZE, b1, b2); |
| 84 | mb(); |
| 85 | count++; |
| 86 | mb(); |
| 87 | } |
| 88 | if (count > max) |
| 89 | max = count; |
| 90 | } |
| 91 | |
| 92 | speed = max * (HZ * BENCH_SIZE / 1024); |
| 93 | tmpl->speed = speed; |
| 94 | |
| 95 | printk(KERN_INFO " %-10s: %5d.%03d MB/sec\n", tmpl->name, |
| 96 | speed / 1000, speed % 1000); |
| 97 | } |
| 98 | |
| 99 | static int __init |
| 100 | calibrate_xor_blocks(void) |
| 101 | { |
| 102 | void *b1, *b2; |
| 103 | struct xor_block_template *f, *fastest; |
| 104 | |
| 105 | /* |
| 106 | * Note: Since the memory is not actually used for _anything_ but to |
| 107 | * test the XOR speed, we don't really want kmemcheck to warn about |
| 108 | * reading uninitialized bytes here. |
| 109 | */ |
| 110 | b1 = (void *) __get_free_pages(GFP_KERNEL | __GFP_NOTRACK, 2); |
| 111 | if (!b1) { |
| 112 | printk(KERN_WARNING "xor: Yikes! No memory available.\n"); |
| 113 | return -ENOMEM; |
| 114 | } |
| 115 | b2 = b1 + 2*PAGE_SIZE + BENCH_SIZE; |
| 116 | |
| 117 | /* |
| 118 | * If this arch/cpu has a short-circuited selection, don't loop through |
| 119 | * all the possible functions, just test the best one |
| 120 | */ |
| 121 | |
| 122 | fastest = NULL; |
| 123 | |
| 124 | #ifdef XOR_SELECT_TEMPLATE |
| 125 | fastest = XOR_SELECT_TEMPLATE(fastest); |
| 126 | #endif |
| 127 | |
| 128 | #define xor_speed(templ) do_xor_speed((templ), b1, b2) |
| 129 | |
| 130 | if (fastest) { |
| 131 | printk(KERN_INFO "xor: automatically using best " |
| 132 | "checksumming function: %s\n", |
| 133 | fastest->name); |
| 134 | xor_speed(fastest); |
| 135 | } else { |
| 136 | printk(KERN_INFO "xor: measuring software checksum speed\n"); |
| 137 | XOR_TRY_TEMPLATES; |
| 138 | fastest = template_list; |
| 139 | for (f = fastest; f; f = f->next) |
| 140 | if (f->speed > fastest->speed) |
| 141 | fastest = f; |
| 142 | } |
| 143 | |
| 144 | printk(KERN_INFO "xor: using function: %s (%d.%03d MB/sec)\n", |
| 145 | fastest->name, fastest->speed / 1000, fastest->speed % 1000); |
| 146 | |
| 147 | #undef xor_speed |
| 148 | |
| 149 | free_pages((unsigned long)b1, 2); |
| 150 | |
| 151 | active_template = fastest; |
| 152 | return 0; |
| 153 | } |
| 154 | |
| 155 | static __exit void xor_exit(void) { } |
| 156 | |
| 157 | MODULE_LICENSE("GPL"); |
| 158 | |
| 159 | /* when built-in xor.o must initialize before drivers/md/md.o */ |
| 160 | core_initcall(calibrate_xor_blocks); |
| 161 | module_exit(xor_exit); |
| 162 |
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