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1 | /* -*- linux-c -*- ------------------------------------------------------- * |
2 | * | |
3 | * Copyright 2002 H. Peter Anvin - All Rights Reserved | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License as published by | |
7 | * the Free Software Foundation, Inc., 53 Temple Place Ste 330, | |
8 | * Bostom MA 02111-1307, USA; either version 2 of the License, or | |
9 | * (at your option) any later version; incorporated herein by reference. | |
10 | * | |
11 | * ----------------------------------------------------------------------- */ | |
12 | ||
13 | /* | |
14 | * raid6algos.c | |
15 | * | |
16 | * Algorithm list and algorithm selection for RAID-6 | |
17 | */ | |
18 | ||
19 | #include "raid6.h" | |
20 | #ifndef __KERNEL__ | |
21 | #include <sys/mman.h> | |
22 | #endif | |
23 | ||
24 | struct raid6_calls raid6_call; | |
25 | ||
26 | /* Various routine sets */ | |
27 | extern const struct raid6_calls raid6_intx1; | |
28 | extern const struct raid6_calls raid6_intx2; | |
29 | extern const struct raid6_calls raid6_intx4; | |
30 | extern const struct raid6_calls raid6_intx8; | |
31 | extern const struct raid6_calls raid6_intx16; | |
32 | extern const struct raid6_calls raid6_intx32; | |
33 | extern const struct raid6_calls raid6_mmxx1; | |
34 | extern const struct raid6_calls raid6_mmxx2; | |
35 | extern const struct raid6_calls raid6_sse1x1; | |
36 | extern const struct raid6_calls raid6_sse1x2; | |
37 | extern const struct raid6_calls raid6_sse2x1; | |
38 | extern const struct raid6_calls raid6_sse2x2; | |
39 | extern const struct raid6_calls raid6_sse2x4; | |
40 | extern const struct raid6_calls raid6_altivec1; | |
41 | extern const struct raid6_calls raid6_altivec2; | |
42 | extern const struct raid6_calls raid6_altivec4; | |
43 | extern const struct raid6_calls raid6_altivec8; | |
44 | ||
45 | const struct raid6_calls * const raid6_algos[] = { | |
46 | &raid6_intx1, | |
47 | &raid6_intx2, | |
48 | &raid6_intx4, | |
49 | &raid6_intx8, | |
50 | #if defined(__ia64__) | |
51 | &raid6_intx16, | |
52 | &raid6_intx32, | |
53 | #endif | |
54 | #if defined(__i386__) | |
55 | &raid6_mmxx1, | |
56 | &raid6_mmxx2, | |
57 | &raid6_sse1x1, | |
58 | &raid6_sse1x2, | |
59 | &raid6_sse2x1, | |
60 | &raid6_sse2x2, | |
61 | #endif | |
62 | #if defined(__x86_64__) | |
63 | &raid6_sse2x1, | |
64 | &raid6_sse2x2, | |
65 | &raid6_sse2x4, | |
66 | #endif | |
67 | #ifdef CONFIG_ALTIVEC | |
68 | &raid6_altivec1, | |
69 | &raid6_altivec2, | |
70 | &raid6_altivec4, | |
71 | &raid6_altivec8, | |
72 | #endif | |
73 | NULL | |
74 | }; | |
75 | ||
76 | #ifdef __KERNEL__ | |
77 | #define RAID6_TIME_JIFFIES_LG2 4 | |
78 | #else | |
79 | /* Need more time to be stable in userspace */ | |
80 | #define RAID6_TIME_JIFFIES_LG2 9 | |
81 | #endif | |
82 | ||
83 | /* Try to pick the best algorithm */ | |
84 | /* This code uses the gfmul table as convenient data set to abuse */ | |
85 | ||
86 | int __init raid6_select_algo(void) | |
87 | { | |
88 | const struct raid6_calls * const * algo; | |
89 | const struct raid6_calls * best; | |
90 | char *syndromes; | |
91 | void *dptrs[(65536/PAGE_SIZE)+2]; | |
92 | int i, disks; | |
93 | unsigned long perf, bestperf; | |
94 | int bestprefer; | |
95 | unsigned long j0, j1; | |
96 | ||
97 | disks = (65536/PAGE_SIZE)+2; | |
98 | for ( i = 0 ; i < disks-2 ; i++ ) { | |
99 | dptrs[i] = ((char *)raid6_gfmul) + PAGE_SIZE*i; | |
100 | } | |
101 | ||
102 | /* Normal code - use a 2-page allocation to avoid D$ conflict */ | |
103 | syndromes = (void *) __get_free_pages(GFP_KERNEL, 1); | |
104 | ||
105 | if ( !syndromes ) { | |
106 | printk("raid6: Yikes! No memory available.\n"); | |
107 | return -ENOMEM; | |
108 | } | |
109 | ||
110 | dptrs[disks-2] = syndromes; | |
111 | dptrs[disks-1] = syndromes + PAGE_SIZE; | |
112 | ||
113 | bestperf = 0; bestprefer = 0; best = NULL; | |
114 | ||
115 | for ( algo = raid6_algos ; *algo ; algo++ ) { | |
116 | if ( !(*algo)->valid || (*algo)->valid() ) { | |
117 | perf = 0; | |
118 | ||
119 | preempt_disable(); | |
120 | j0 = jiffies; | |
121 | while ( (j1 = jiffies) == j0 ) | |
122 | cpu_relax(); | |
123 | while ( (jiffies-j1) < (1 << RAID6_TIME_JIFFIES_LG2) ) { | |
124 | (*algo)->gen_syndrome(disks, PAGE_SIZE, dptrs); | |
125 | perf++; | |
126 | } | |
127 | preempt_enable(); | |
128 | ||
129 | if ( (*algo)->prefer > bestprefer || | |
130 | ((*algo)->prefer == bestprefer && | |
131 | perf > bestperf) ) { | |
132 | best = *algo; | |
133 | bestprefer = best->prefer; | |
134 | bestperf = perf; | |
135 | } | |
136 | printk("raid6: %-8s %5ld MB/s\n", (*algo)->name, | |
137 | (perf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2)); | |
138 | } | |
139 | } | |
140 | ||
141 | if ( best ) | |
142 | printk("raid6: using algorithm %s (%ld MB/s)\n", | |
143 | best->name, | |
144 | (bestperf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2)); | |
145 | else | |
146 | printk("raid6: Yikes! No algorithm found!\n"); | |
147 | ||
148 | raid6_call = *best; | |
149 | ||
150 | free_pages((unsigned long)syndromes, 1); | |
151 | ||
152 | return best ? 0 : -EINVAL; | |
153 | } |