175 lines
3.8 KiB
C
175 lines
3.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/*
|
|
* 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.
|
|
*/
|
|
|
|
#define BH_TRACE 0
|
|
#include <linux/module.h>
|
|
#include <linux/gfp.h>
|
|
#include <linux/raid/xor.h>
|
|
#include <linux/jiffies.h>
|
|
#include <linux/preempt.h>
|
|
#include <asm/xor.h>
|
|
|
|
#ifndef XOR_SELECT_TEMPLATE
|
|
#define XOR_SELECT_TEMPLATE(x) (x)
|
|
#endif
|
|
|
|
/* The xor routines to use. */
|
|
static struct xor_block_template *active_template;
|
|
|
|
void
|
|
xor_blocks(unsigned int src_count, unsigned int bytes, void *dest, void **srcs)
|
|
{
|
|
unsigned long *p1, *p2, *p3, *p4;
|
|
|
|
p1 = (unsigned long *) srcs[0];
|
|
if (src_count == 1) {
|
|
active_template->do_2(bytes, dest, p1);
|
|
return;
|
|
}
|
|
|
|
p2 = (unsigned long *) srcs[1];
|
|
if (src_count == 2) {
|
|
active_template->do_3(bytes, dest, p1, p2);
|
|
return;
|
|
}
|
|
|
|
p3 = (unsigned long *) srcs[2];
|
|
if (src_count == 3) {
|
|
active_template->do_4(bytes, dest, p1, p2, p3);
|
|
return;
|
|
}
|
|
|
|
p4 = (unsigned long *) srcs[3];
|
|
active_template->do_5(bytes, dest, p1, p2, p3, p4);
|
|
}
|
|
EXPORT_SYMBOL(xor_blocks);
|
|
|
|
/* Set of all registered templates. */
|
|
static struct xor_block_template *__initdata template_list;
|
|
|
|
#ifndef MODULE
|
|
static void __init do_xor_register(struct xor_block_template *tmpl)
|
|
{
|
|
tmpl->next = template_list;
|
|
template_list = tmpl;
|
|
}
|
|
|
|
static int __init register_xor_blocks(void)
|
|
{
|
|
active_template = XOR_SELECT_TEMPLATE(NULL);
|
|
|
|
if (!active_template) {
|
|
#define xor_speed do_xor_register
|
|
// register all the templates and pick the first as the default
|
|
XOR_TRY_TEMPLATES;
|
|
#undef xor_speed
|
|
active_template = template_list;
|
|
}
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
#define BENCH_SIZE 4096
|
|
#define REPS 800U
|
|
|
|
static void __init
|
|
do_xor_speed(struct xor_block_template *tmpl, void *b1, void *b2)
|
|
{
|
|
int speed;
|
|
unsigned long reps;
|
|
ktime_t min, start, t0;
|
|
|
|
tmpl->next = template_list;
|
|
template_list = tmpl;
|
|
|
|
preempt_disable();
|
|
|
|
reps = 0;
|
|
t0 = ktime_get();
|
|
/* delay start until time has advanced */
|
|
while ((start = ktime_get()) == t0)
|
|
cpu_relax();
|
|
do {
|
|
mb(); /* prevent loop optimization */
|
|
tmpl->do_2(BENCH_SIZE, b1, b2);
|
|
mb();
|
|
} while (reps++ < REPS || (t0 = ktime_get()) == start);
|
|
min = ktime_sub(t0, start);
|
|
|
|
preempt_enable();
|
|
|
|
// bytes/ns == GB/s, multiply by 1000 to get MB/s [not MiB/s]
|
|
speed = (1000 * reps * BENCH_SIZE) / (unsigned int)ktime_to_ns(min);
|
|
tmpl->speed = speed;
|
|
|
|
pr_info(" %-16s: %5d MB/sec\n", tmpl->name, speed);
|
|
}
|
|
|
|
static int __init
|
|
calibrate_xor_blocks(void)
|
|
{
|
|
void *b1, *b2;
|
|
struct xor_block_template *f, *fastest;
|
|
|
|
fastest = XOR_SELECT_TEMPLATE(NULL);
|
|
|
|
if (fastest) {
|
|
printk(KERN_INFO "xor: automatically using best "
|
|
"checksumming function %-10s\n",
|
|
fastest->name);
|
|
goto out;
|
|
}
|
|
|
|
b1 = (void *) __get_free_pages(GFP_KERNEL, 2);
|
|
if (!b1) {
|
|
printk(KERN_WARNING "xor: Yikes! No memory available.\n");
|
|
return -ENOMEM;
|
|
}
|
|
b2 = b1 + 2*PAGE_SIZE + BENCH_SIZE;
|
|
|
|
/*
|
|
* If this arch/cpu has a short-circuited selection, don't loop through
|
|
* all the possible functions, just test the best one
|
|
*/
|
|
|
|
#define xor_speed(templ) do_xor_speed((templ), b1, b2)
|
|
|
|
printk(KERN_INFO "xor: measuring software checksum speed\n");
|
|
template_list = NULL;
|
|
XOR_TRY_TEMPLATES;
|
|
fastest = template_list;
|
|
for (f = fastest; f; f = f->next)
|
|
if (f->speed > fastest->speed)
|
|
fastest = f;
|
|
|
|
pr_info("xor: using function: %s (%d MB/sec)\n",
|
|
fastest->name, fastest->speed);
|
|
|
|
#undef xor_speed
|
|
|
|
free_pages((unsigned long)b1, 2);
|
|
out:
|
|
active_template = fastest;
|
|
return 0;
|
|
}
|
|
|
|
static __exit void xor_exit(void) { }
|
|
|
|
MODULE_DESCRIPTION("RAID-5 checksumming functions");
|
|
MODULE_LICENSE("GPL");
|
|
|
|
#ifndef MODULE
|
|
/* when built-in xor.o must initialize before drivers/md/md.o */
|
|
core_initcall(register_xor_blocks);
|
|
#endif
|
|
|
|
module_init(calibrate_xor_blocks);
|
|
module_exit(xor_exit);
|