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[/] [or1k/] [trunk/] [linux/] [linux-2.4/] [drivers/] [md/] [xor.c] - Rev 1765
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/* * xor.c : Multiple Devices driver for Linux * * Copyright (C) 1996, 1997, 1998, 1999, 2000, * Ingo Molnar, Matti Aarnio, Jakub Jelinek, Richard Henderson. * * Dispatch optimized RAID-5 checksumming functions. * * 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; either version 2, or (at your option) * any later version. * * You should have received a copy of the GNU General Public License * (for example /usr/src/linux/COPYING); if not, write to the Free * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #define BH_TRACE 0 #include <linux/module.h> #include <linux/raid/md.h> #include <linux/raid/xor.h> #include <asm/xor.h> /* The xor routines to use. */ static struct xor_block_template *active_template; void xor_block(unsigned int count, struct buffer_head **bh_ptr) { unsigned long *p0, *p1, *p2, *p3, *p4; unsigned long bytes = bh_ptr[0]->b_size; p0 = (unsigned long *) bh_ptr[0]->b_data; p1 = (unsigned long *) bh_ptr[1]->b_data; if (count == 2) { active_template->do_2(bytes, p0, p1); return; } p2 = (unsigned long *) bh_ptr[2]->b_data; if (count == 3) { active_template->do_3(bytes, p0, p1, p2); return; } p3 = (unsigned long *) bh_ptr[3]->b_data; if (count == 4) { active_template->do_4(bytes, p0, p1, p2, p3); return; } p4 = (unsigned long *) bh_ptr[4]->b_data; active_template->do_5(bytes, p0, p1, p2, p3, p4); } /* Set of all registered templates. */ static struct xor_block_template *template_list; #define BENCH_SIZE (PAGE_SIZE) static void do_xor_speed(struct xor_block_template *tmpl, void *b1, void *b2) { int speed; unsigned long now; int i, count, max; tmpl->next = template_list; template_list = tmpl; /* * Count the number of XORs done during a whole jiffy, and use * this to calculate the speed of checksumming. We use a 2-page * allocation to have guaranteed color L1-cache layout. */ max = 0; for (i = 0; i < 5; i++) { now = jiffies; count = 0; while (jiffies == now) { mb(); tmpl->do_2(BENCH_SIZE, b1, b2); mb(); count++; mb(); } if (count > max) max = count; } speed = max * (HZ * BENCH_SIZE / 1024); tmpl->speed = speed; printk(" %-10s: %5d.%03d MB/sec\n", tmpl->name, speed / 1000, speed % 1000); } static int calibrate_xor_block(void) { void *b1, *b2; struct xor_block_template *f, *fastest; b1 = (void *) md__get_free_pages(GFP_KERNEL, 2); if (! b1) { printk("raid5: Yikes! No memory available.\n"); return -ENOMEM; } b2 = b1 + 2*PAGE_SIZE + BENCH_SIZE; printk(KERN_INFO "raid5: measuring checksumming speed\n"); sti(); #define xor_speed(templ) do_xor_speed((templ), b1, b2) XOR_TRY_TEMPLATES; #undef xor_speed free_pages((unsigned long)b1, 2); fastest = template_list; for (f = fastest; f; f = f->next) if (f->speed > fastest->speed) fastest = f; #ifdef XOR_SELECT_TEMPLATE fastest = XOR_SELECT_TEMPLATE(fastest); #endif active_template = fastest; printk("raid5: using function: %s (%d.%03d MB/sec)\n", fastest->name, fastest->speed / 1000, fastest->speed % 1000); return 0; } MD_EXPORT_SYMBOL(xor_block); MODULE_LICENSE("GPL"); module_init(calibrate_xor_block);