[PATCH v3 4/6] lib/bitmap: add tests for find_nth_bit()

From: Yury Norov
Date: Sat Sep 17 2022 - 23:07:57 EST


Add functional and performance tests for find_nth_bit().

Signed-off-by: Yury Norov <yury.norov@xxxxxxxxx>
---
lib/find_bit_benchmark.c | 18 +++++++++++++++
lib/test_bitmap.c | 47 ++++++++++++++++++++++++++++++++++++++--
2 files changed, 63 insertions(+), 2 deletions(-)

diff --git a/lib/find_bit_benchmark.c b/lib/find_bit_benchmark.c
index db904b57d4b8..10754586403b 100644
--- a/lib/find_bit_benchmark.c
+++ b/lib/find_bit_benchmark.c
@@ -115,6 +115,22 @@ static int __init test_find_last_bit(const void *bitmap, unsigned long len)
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)
{
@@ -142,6 +158,7 @@ static int __init find_bit_test(void)
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
@@ -164,6 +181,7 @@ static int __init find_bit_test(void)
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);
diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c
index 98754ff9fe68..da52dc759c95 100644
--- a/lib/test_bitmap.c
+++ b/lib/test_bitmap.c
@@ -16,6 +16,8 @@

#include "../tools/testing/selftests/kselftest_module.h"

+#define EXP1_IN_BITS (sizeof(exp1) * 8)
+
KSTM_MODULE_GLOBALS();

static char pbl_buffer[PAGE_SIZE] __initdata;
@@ -219,6 +221,47 @@ static void __init test_zero_clear(void)
expect_eq_pbl("", bmap, 1024);
}

+static void __init test_find_nth_bit(void)
+{
+ unsigned long b, bit, cnt = 0;
+ DECLARE_BITMAP(bmap, 64 * 3);
+
+ bitmap_zero(bmap, 64 * 3);
+ __set_bit(10, bmap);
+ __set_bit(20, bmap);
+ __set_bit(30, bmap);
+ __set_bit(40, bmap);
+ __set_bit(50, bmap);
+ __set_bit(60, bmap);
+ __set_bit(80, bmap);
+ __set_bit(123, bmap);
+
+ expect_eq_uint(10, find_nth_bit(bmap, 64 * 3, 0));
+ expect_eq_uint(20, find_nth_bit(bmap, 64 * 3, 1));
+ expect_eq_uint(30, find_nth_bit(bmap, 64 * 3, 2));
+ expect_eq_uint(40, find_nth_bit(bmap, 64 * 3, 3));
+ expect_eq_uint(50, find_nth_bit(bmap, 64 * 3, 4));
+ expect_eq_uint(60, find_nth_bit(bmap, 64 * 3, 5));
+ expect_eq_uint(80, find_nth_bit(bmap, 64 * 3, 6));
+ expect_eq_uint(123, find_nth_bit(bmap, 64 * 3, 7));
+ expect_eq_uint(64 * 3, find_nth_bit(bmap, 64 * 3, 8));
+
+ expect_eq_uint(10, find_nth_bit(bmap, 64 * 3 - 1, 0));
+ expect_eq_uint(20, find_nth_bit(bmap, 64 * 3 - 1, 1));
+ expect_eq_uint(30, find_nth_bit(bmap, 64 * 3 - 1, 2));
+ expect_eq_uint(40, find_nth_bit(bmap, 64 * 3 - 1, 3));
+ expect_eq_uint(50, find_nth_bit(bmap, 64 * 3 - 1, 4));
+ expect_eq_uint(60, find_nth_bit(bmap, 64 * 3 - 1, 5));
+ expect_eq_uint(80, find_nth_bit(bmap, 64 * 3 - 1, 6));
+ expect_eq_uint(123, find_nth_bit(bmap, 64 * 3 - 1, 7));
+ expect_eq_uint(64 * 3 - 1, find_nth_bit(bmap, 64 * 3 - 1, 8));
+
+ for_each_set_bit(bit, exp1, EXP1_IN_BITS) {
+ b = find_nth_bit(exp1, EXP1_IN_BITS, cnt++);
+ expect_eq_uint(b, bit);
+ }
+}
+
static void __init test_fill_set(void)
{
DECLARE_BITMAP(bmap, 1024);
@@ -557,8 +600,6 @@ static void __init test_bitmap_parse(void)
}
}

-#define EXP1_IN_BITS (sizeof(exp1) * 8)
-
static void __init test_bitmap_arr32(void)
{
unsigned int nbits, next_bit;
@@ -952,6 +993,8 @@ static void __init selftest(void)
test_bitmap_cut();
test_bitmap_print_buf();
test_bitmap_const_eval();
+
+ test_find_nth_bit();
}

KSTM_MODULE_LOADERS(test_bitmap);
--
2.34.1