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
|
/* -*- linux-c -*- ------------------------------------------------------- *
*
* Copyright 2002 H. Peter Anvin - All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, Inc., 53 Temple Place Ste 330,
* Bostom MA 02111-1307, USA; either version 2 of the License, or
* (at your option) any later version; incorporated herein by reference.
*
* ----------------------------------------------------------------------- */
/*
* raid6algos.c
*
* Algorithm list and algorithm selection for RAID-6
*/
#include "raid6.h"
#ifndef __KERNEL__
#include <sys/mman.h>
#endif
struct raid6_calls raid6_call;
/* Various routine sets */
extern const struct raid6_calls raid6_intx1;
extern const struct raid6_calls raid6_intx2;
extern const struct raid6_calls raid6_intx4;
extern const struct raid6_calls raid6_intx8;
extern const struct raid6_calls raid6_intx16;
extern const struct raid6_calls raid6_intx32;
extern const struct raid6_calls raid6_mmxx1;
extern const struct raid6_calls raid6_mmxx2;
extern const struct raid6_calls raid6_sse1x1;
extern const struct raid6_calls raid6_sse1x2;
extern const struct raid6_calls raid6_sse2x1;
extern const struct raid6_calls raid6_sse2x2;
extern const struct raid6_calls raid6_sse2x4;
extern const struct raid6_calls raid6_altivec1;
extern const struct raid6_calls raid6_altivec2;
extern const struct raid6_calls raid6_altivec4;
extern const struct raid6_calls raid6_altivec8;
const struct raid6_calls * const raid6_algos[] = {
&raid6_intx1,
&raid6_intx2,
&raid6_intx4,
&raid6_intx8,
#if defined(__ia64__)
&raid6_intx16,
&raid6_intx32,
#endif
#if defined(__i386__)
&raid6_mmxx1,
&raid6_mmxx2,
&raid6_sse1x1,
&raid6_sse1x2,
&raid6_sse2x1,
&raid6_sse2x2,
#endif
#if defined(__x86_64__)
&raid6_sse2x1,
&raid6_sse2x2,
&raid6_sse2x4,
#endif
#ifdef CONFIG_ALTIVEC
&raid6_altivec1,
&raid6_altivec2,
&raid6_altivec4,
&raid6_altivec8,
#endif
NULL
};
#ifdef __KERNEL__
#define RAID6_TIME_JIFFIES_LG2 4
#else
/* Need more time to be stable in userspace */
#define RAID6_TIME_JIFFIES_LG2 9
#endif
/* Try to pick the best algorithm */
/* This code uses the gfmul table as convenient data set to abuse */
int __init raid6_select_algo(void)
{
const struct raid6_calls * const * algo;
const struct raid6_calls * best;
char *syndromes;
void *dptrs[(65536/PAGE_SIZE)+2];
int i, disks;
unsigned long perf, bestperf;
int bestprefer;
unsigned long j0, j1;
disks = (65536/PAGE_SIZE)+2;
for ( i = 0 ; i < disks-2 ; i++ ) {
dptrs[i] = ((char *)raid6_gfmul) + PAGE_SIZE*i;
}
/* Normal code - use a 2-page allocation to avoid D$ conflict */
syndromes = (void *) __get_free_pages(GFP_KERNEL, 1);
if ( !syndromes ) {
printk("raid6: Yikes! No memory available.\n");
return -ENOMEM;
}
dptrs[disks-2] = syndromes;
dptrs[disks-1] = syndromes + PAGE_SIZE;
bestperf = 0; bestprefer = 0; best = NULL;
for ( algo = raid6_algos ; *algo ; algo++ ) {
if ( !(*algo)->valid || (*algo)->valid() ) {
perf = 0;
preempt_disable();
j0 = jiffies;
while ( (j1 = jiffies) == j0 )
cpu_relax();
while ( (jiffies-j1) < (1 << RAID6_TIME_JIFFIES_LG2) ) {
(*algo)->gen_syndrome(disks, PAGE_SIZE, dptrs);
perf++;
}
preempt_enable();
if ( (*algo)->prefer > bestprefer ||
((*algo)->prefer == bestprefer &&
perf > bestperf) ) {
best = *algo;
bestprefer = best->prefer;
bestperf = perf;
}
printk("raid6: %-8s %5ld MB/s\n", (*algo)->name,
(perf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2));
}
}
if ( best )
printk("raid6: using algorithm %s (%ld MB/s)\n",
best->name,
(bestperf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2));
else
printk("raid6: Yikes! No algorithm found!\n");
raid6_call = *best;
free_pages((unsigned long)syndromes, 1);
return best ? 0 : -EINVAL;
}
|
