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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219// 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. */static int __init test_find_first_bit(const void *bitmap, unsigned long len){ static DECLARE_BITMAP(cp, BITMAP_LEN) __initdata; unsigned long i, cnt; ktime_t time;
bitmap_copy(cp, bitmap, BITMAP_LEN);
time = ktime_get(); for (cnt = i = 0; i < len; cnt++) { i = find_first_bit(cp, len); __clear_bit(i, cp); } time = ktime_get() - time; pr_err("find_first_bit: %18llu ns, %6ld iterations\n", time, cnt);
return 0;}
static int __init test_find_first_and_bit(const void *bitmap, const void *bitmap2, unsigned long len){ static DECLARE_BITMAP(cp, BITMAP_LEN) __initdata; unsigned long i, cnt; ktime_t time;
bitmap_copy(cp, bitmap, BITMAP_LEN);
time = ktime_get(); for (cnt = i = 0; i < len; cnt++) { i = find_first_and_bit(cp, bitmap2, len); __clear_bit(i, cp); } time = ktime_get() - time; pr_err("find_first_and_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_nth_bit(const unsigned long *bitmap, unsigned long len){ unsigned long l, n, w = bitmap_weight(bitmap, len); ktime_t time;
time = ktime_get(); for (n = 0; n < w; n++) { l = find_nth_bit(bitmap, len, n); WARN_ON(l >= len); } time = ktime_get() - time; pr_err("find_nth_bit: %18llu ns, %6ld iterations\n", time, w);
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 __inittest_bitmap_find_next_zero_area_off(unsigned long *bitmap, unsigned long len){ unsigned long i, cnt; ktime_t time;
time = ktime_get(); for (cnt = i = 0; i < BITMAP_LEN; cnt++) i = bitmap_find_next_zero_area_off(bitmap, BITMAP_LEN, i, 8, 0, 0) + 1; time = ktime_get() - time; pr_err("bitmap_find_next_zero_area_off:%7llu 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_bitmap_find_next_zero_area_off(bitmap, BITMAP_LEN); test_find_next_bit(bitmap, BITMAP_LEN); test_find_next_zero_bit(bitmap, BITMAP_LEN); test_find_last_bit(bitmap, BITMAP_LEN); test_find_nth_bit(bitmap, BITMAP_LEN / 10);
/* * 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_first_and_bit(bitmap, bitmap2, BITMAP_LEN / 2); 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(get_random_u32_below(BITMAP_LEN), bitmap); __set_bit(get_random_u32_below(BITMAP_LEN), bitmap2); }
test_bitmap_find_next_zero_area_off(bitmap, BITMAP_LEN); test_find_next_bit(bitmap, BITMAP_LEN); test_find_next_zero_bit(bitmap, BITMAP_LEN); test_find_last_bit(bitmap, BITMAP_LEN); test_find_nth_bit(bitmap, BITMAP_LEN); test_find_first_bit(bitmap, BITMAP_LEN); test_find_first_and_bit(bitmap, bitmap2, 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_DESCRIPTION("Test for find_*_bit functions");MODULE_LICENSE("GPL");