159 lines
3.9 KiB
C
159 lines
3.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* Test for find_*_bit functions.
|
|
*
|
|
* Copyright (c) 2017 Cavium.
|
|
*/
|
|
|
|
/*
|
|
* find_bit functions are widely used in kernel, so the successful boot
|
|
* is good enough test for correctness.
|
|
*
|
|
* This test is focused on performance of traversing bitmaps. Two typical
|
|
* scenarios are reproduced:
|
|
* - randomly filled bitmap with approximately equal number of set and
|
|
* cleared bits;
|
|
* - sparse bitmap with few set bits at random positions.
|
|
*/
|
|
|
|
#include <linux/bitops.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/list.h>
|
|
#include <linux/module.h>
|
|
#include <linux/printk.h>
|
|
#include <linux/random.h>
|
|
|
|
#define BITMAP_LEN (4096UL * 8 * 10)
|
|
#define SPARSE 500
|
|
|
|
static DECLARE_BITMAP(bitmap, BITMAP_LEN) __initdata;
|
|
static DECLARE_BITMAP(bitmap2, BITMAP_LEN) __initdata;
|
|
|
|
/*
|
|
* This is Schlemiel the Painter's algorithm. It should be called after
|
|
* all other tests for the same bitmap because it sets all bits of bitmap to 1.
|
|
*/
|
|
static int __init test_find_first_bit(void *bitmap, unsigned long len)
|
|
{
|
|
unsigned long i, cnt;
|
|
ktime_t time;
|
|
|
|
time = ktime_get();
|
|
for (cnt = i = 0; i < len; cnt++) {
|
|
i = find_first_bit(bitmap, len);
|
|
__clear_bit(i, bitmap);
|
|
}
|
|
time = ktime_get() - time;
|
|
pr_err("find_first_bit: %18llu ns, %6ld iterations\n", time, cnt);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int __init test_find_next_bit(const void *bitmap, unsigned long len)
|
|
{
|
|
unsigned long i, cnt;
|
|
ktime_t time;
|
|
|
|
time = ktime_get();
|
|
for (cnt = i = 0; i < BITMAP_LEN; cnt++)
|
|
i = find_next_bit(bitmap, BITMAP_LEN, i) + 1;
|
|
time = ktime_get() - time;
|
|
pr_err("find_next_bit: %18llu ns, %6ld iterations\n", time, cnt);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int __init test_find_next_zero_bit(const void *bitmap, unsigned long len)
|
|
{
|
|
unsigned long i, cnt;
|
|
ktime_t time;
|
|
|
|
time = ktime_get();
|
|
for (cnt = i = 0; i < BITMAP_LEN; cnt++)
|
|
i = find_next_zero_bit(bitmap, len, i) + 1;
|
|
time = ktime_get() - time;
|
|
pr_err("find_next_zero_bit: %18llu ns, %6ld iterations\n", time, cnt);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int __init test_find_last_bit(const void *bitmap, unsigned long len)
|
|
{
|
|
unsigned long l, cnt = 0;
|
|
ktime_t time;
|
|
|
|
time = ktime_get();
|
|
do {
|
|
cnt++;
|
|
l = find_last_bit(bitmap, len);
|
|
if (l >= len)
|
|
break;
|
|
len = l;
|
|
} while (len);
|
|
time = ktime_get() - time;
|
|
pr_err("find_last_bit: %18llu ns, %6ld iterations\n", time, cnt);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int __init test_find_next_and_bit(const void *bitmap,
|
|
const void *bitmap2, unsigned long len)
|
|
{
|
|
unsigned long i, cnt;
|
|
ktime_t time;
|
|
|
|
time = ktime_get();
|
|
for (cnt = i = 0; i < BITMAP_LEN; cnt++)
|
|
i = find_next_and_bit(bitmap, bitmap2, BITMAP_LEN, i + 1);
|
|
time = ktime_get() - time;
|
|
pr_err("find_next_and_bit: %18llu ns, %6ld iterations\n", time, cnt);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int __init find_bit_test(void)
|
|
{
|
|
unsigned long nbits = BITMAP_LEN / SPARSE;
|
|
|
|
pr_err("\nStart testing find_bit() with random-filled bitmap\n");
|
|
|
|
get_random_bytes(bitmap, sizeof(bitmap));
|
|
get_random_bytes(bitmap2, sizeof(bitmap2));
|
|
|
|
test_find_next_bit(bitmap, BITMAP_LEN);
|
|
test_find_next_zero_bit(bitmap, BITMAP_LEN);
|
|
test_find_last_bit(bitmap, BITMAP_LEN);
|
|
|
|
/*
|
|
* test_find_first_bit() may take some time, so
|
|
* traverse only part of bitmap to avoid soft lockup.
|
|
*/
|
|
test_find_first_bit(bitmap, BITMAP_LEN / 10);
|
|
test_find_next_and_bit(bitmap, bitmap2, BITMAP_LEN);
|
|
|
|
pr_err("\nStart testing find_bit() with sparse bitmap\n");
|
|
|
|
bitmap_zero(bitmap, BITMAP_LEN);
|
|
bitmap_zero(bitmap2, BITMAP_LEN);
|
|
|
|
while (nbits--) {
|
|
__set_bit(prandom_u32() % BITMAP_LEN, bitmap);
|
|
__set_bit(prandom_u32() % BITMAP_LEN, bitmap2);
|
|
}
|
|
|
|
test_find_next_bit(bitmap, BITMAP_LEN);
|
|
test_find_next_zero_bit(bitmap, BITMAP_LEN);
|
|
test_find_last_bit(bitmap, BITMAP_LEN);
|
|
test_find_first_bit(bitmap, BITMAP_LEN);
|
|
test_find_next_and_bit(bitmap, bitmap2, BITMAP_LEN);
|
|
|
|
/*
|
|
* Everything is OK. Return error just to let user run benchmark
|
|
* again without annoying rmmod.
|
|
*/
|
|
return -EINVAL;
|
|
}
|
|
module_init(find_bit_test);
|
|
|
|
MODULE_LICENSE("GPL");
|