[net-next-2.6.git] / drivers / md / raid6algos.c

/* -*- 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,
 *   Boston 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 <linux/raid/pq.h>
#ifndef __KERNEL__
#include <sys/mman.h>
#include <stdio.h>
#else
#if !RAID6_USE_EMPTY_ZERO_PAGE
/* In .bss so it's zeroed */
const char raid6_empty_zero_page[PAGE_SIZE] __attribute__((aligned(256)));
EXPORT_SYMBOL(raid6_empty_zero_page);
#endif
#endif

struct raid6_calls raid6_call;
EXPORT_SYMBOL_GPL(raid6_call);

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__) && !defined(__arch_um__)
	&raid6_mmxx1,
	&raid6_mmxx2,
	&raid6_sse1x1,
	&raid6_sse1x2,
	&raid6_sse2x1,
	&raid6_sse2x2,
#endif
#if defined(__x86_64__) && !defined(__arch_um__)
	&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
#define time_before(x, y) ((x) < (y))
#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 (time_before(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));
		raid6_call = *best;
	} else
		printk("raid6: Yikes!  No algorithm found!\n");

	free_pages((unsigned long)syndromes, 1);

	return best ? 0 : -EINVAL;
}

static void raid6_exit(void)
{
	do { } while (0);
}

subsys_initcall(raid6_select_algo);
module_exit(raid6_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("RAID6 Q-syndrome calculations");
Commit	Line	Data
1da177e4 LT	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,
93ed05e2	8	* Boston MA 02111-1307, USA; either version 2 of the License, or
1da177e4 LT	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
f701d589	19	#include <linux/raid/pq.h>
1da177e4 LT	20	#ifndef __KERNEL__
1da177e4 LT	21	#include <sys/mman.h>
d7e70ba4	22	#include <stdio.h>
f701d589 DW	23	#else
	24	#if !RAID6_USE_EMPTY_ZERO_PAGE
	25	/* In .bss so it's zeroed */
	26	const char raid6_empty_zero_page[PAGE_SIZE] __attribute__((aligned(256)));
	27	EXPORT_SYMBOL(raid6_empty_zero_page);
	28	#endif
1da177e4 LT	29	#endif
	30
	31	struct raid6_calls raid6_call;
f701d589	32	EXPORT_SYMBOL_GPL(raid6_call);
1da177e4	33
1da177e4 LT	34	const struct raid6_calls * const raid6_algos[] = {
	35	&raid6_intx1,
	36	&raid6_intx2,
	37	&raid6_intx4,
	38	&raid6_intx8,
	39	#if defined(__ia64__)
	40	&raid6_intx16,
	41	&raid6_intx32,
	42	#endif
ca5cd877	43	#if defined(__i386__) && !defined(__arch_um__)
1da177e4 LT	44	&raid6_mmxx1,
	45	&raid6_mmxx2,
	46	&raid6_sse1x1,
	47	&raid6_sse1x2,
	48	&raid6_sse2x1,
	49	&raid6_sse2x2,
	50	#endif
ca5cd877	51	#if defined(__x86_64__) && !defined(__arch_um__)
1da177e4 LT	52	&raid6_sse2x1,
	53	&raid6_sse2x2,
	54	&raid6_sse2x4,
	55	#endif
	56	#ifdef CONFIG_ALTIVEC
	57	&raid6_altivec1,
	58	&raid6_altivec2,
	59	&raid6_altivec4,
	60	&raid6_altivec8,
	61	#endif
	62	NULL
	63	};
	64
	65	#ifdef __KERNEL__
	66	#define RAID6_TIME_JIFFIES_LG2 4
	67	#else
	68	/* Need more time to be stable in userspace */
	69	#define RAID6_TIME_JIFFIES_LG2 9
f701d589	70	#define time_before(x, y) ((x) < (y))
1da177e4 LT	71	#endif
	72
	73	/* Try to pick the best algorithm */
	74	/* This code uses the gfmul table as convenient data set to abuse */
	75
	76	int __init raid6_select_algo(void)
	77	{
	78	const struct raid6_calls * const * algo;
	79	const struct raid6_calls * best;
	80	char *syndromes;
	81	void *dptrs[(65536/PAGE_SIZE)+2];
	82	int i, disks;
	83	unsigned long perf, bestperf;
	84	int bestprefer;
	85	unsigned long j0, j1;
	86
	87	disks = (65536/PAGE_SIZE)+2;
	88	for ( i = 0 ; i < disks-2 ; i++ ) {
	89	dptrs[i] = ((char )raid6_gfmul) + PAGE_SIZEi;
	90	}
	91
	92	/* Normal code - use a 2-page allocation to avoid D$ conflict */
	93	syndromes = (void *) __get_free_pages(GFP_KERNEL, 1);
	94
	95	if ( !syndromes ) {
	96	printk("raid6: Yikes! No memory available.\n");
	97	return -ENOMEM;
	98	}
	99
	100	dptrs[disks-2] = syndromes;
	101	dptrs[disks-1] = syndromes + PAGE_SIZE;
	102
	103	bestperf = 0; bestprefer = 0; best = NULL;
	104
	105	for ( algo = raid6_algos ; *algo ; algo++ ) {
	106	if ( !(algo)->valid \|\| (algo)->valid() ) {
	107	perf = 0;
	108
	109	preempt_disable();
	110	j0 = jiffies;
	111	while ( (j1 = jiffies) == j0 )
	112	cpu_relax();
62b0559a JL	113	while (time_before(jiffies,
62b0559a JL	114	j1 + (1<<RAID6_TIME_JIFFIES_LG2))) {
1da177e4 LT	115	(*algo)->gen_syndrome(disks, PAGE_SIZE, dptrs);
	116	perf++;
	117	}
	118	preempt_enable();
	119
	120	if ( (*algo)->prefer > bestprefer \|\|
	121	((*algo)->prefer == bestprefer &&
	122	perf > bestperf) ) {
	123	best = *algo;
	124	bestprefer = best->prefer;
	125	bestperf = perf;
	126	}
	127	printk("raid6: %-8s %5ld MB/s\n", (*algo)->name,
	128	(perf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2));
	129	}
	130	}
	131
a5d6839b	132	if (best) {
1da177e4 LT	133	printk("raid6: using algorithm %s (%ld MB/s)\n",
	134	best->name,
	135	(bestperf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2));
a5d6839b AB	136	raid6_call = *best;
a5d6839b AB	137	} else
1da177e4 LT	138	printk("raid6: Yikes! No algorithm found!\n");
1da177e4 LT	139
1da177e4 LT	140	free_pages((unsigned long)syndromes, 1);
	141
	142	return best ? 0 : -EINVAL;
	143	}
f701d589 DW	144
	145	static void raid6_exit(void)
	146	{
	147	do { } while (0);
	148	}
	149
	150	subsys_initcall(raid6_select_algo);
	151	module_exit(raid6_exit);
	152	MODULE_LICENSE("GPL");
0efb9e61	153	MODULE_DESCRIPTION("RAID6 Q-syndrome calculations");