/* -*- 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> #include <stdio.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)); raid6_call = *best; } else printk("raid6: Yikes! No algorithm found!\n"); free_pages((unsigned long)syndromes, 1); return best ? 0 : -EINVAL; }