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From: Yi Sun <yi.sun@unisoc.com>
To: <yury.norov@gmail.com>
Cc: <yi.sun@unisoc.com>, <279644543@qq.com>, <mina86@mina86.com>,
	<mnazarewicz@gmail.com>, <akpm@linux-foundation.org>,
	<akinobu.mita@gmail.com>, <linux-kernel@vger.kernel.org>,
	<tjmercier@google.com>, <fvdl@google.com>, <tglx@kernel.org>,
	<song@kernel.org>, <hch@lst.de>, <minchan@kernel.org>,
	<jstultz@google.com>
Subject: [PATCH v7 1/2] lib: bitmap: add tests for bitmap_find_next_zero_area_off()
Date: Mon, 22 Jun 2026 11:00:35 +0800	[thread overview]
Message-ID: <20260622030036.1744080-2-yi.sun@unisoc.com> (raw)
In-Reply-To: <20260622030036.1744080-1-yi.sun@unisoc.com>

Add functional and performance tests
for bitmap_find_next_zero_area_off().

performance tests partial output:
Start testing find_bit() with random-filled bitmap
[    0.310073] bitmap_find_next_zero_area_off: 852731 ns,   1154 iterations
[    0.311435] find_next_bit:                 1356654 ns, 163975 iterations
Start testing find_bit() with sparse bitmap
[    0.316267] bitmap_find_next_zero_area_off:4426808 ns, 322479 iterations
[    0.316292] find_next_bit:                   15154 ns,    656 iterations

Signed-off-by: Yi Sun <yi.sun@unisoc.com>
---
 lib/find_bit_benchmark.c | 17 +++++++++++++++++
 lib/test_bitmap.c        | 38 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+)

diff --git a/lib/find_bit_benchmark.c b/lib/find_bit_benchmark.c
index 00d9dc61cd46..05305e655f99 100644
--- a/lib/find_bit_benchmark.c
+++ b/lib/find_bit_benchmark.c
@@ -149,6 +149,21 @@ static int __init test_find_next_and_bit(const void *bitmap,
 	return 0;
 }
 
+static int __init
+test_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;
@@ -158,6 +173,7 @@ static int __init find_bit_test(void)
 	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);
@@ -181,6 +197,7 @@ static int __init find_bit_test(void)
 		__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);
diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c
index 69813c10e6c0..8665df77c960 100644
--- a/lib/test_bitmap.c
+++ b/lib/test_bitmap.c
@@ -234,6 +234,43 @@ static void __init test_find_nth_bit(void)
 	}
 }
 
+static void __init
+test_bitmap_find_next_zero_area_off(void)
+{
+	DECLARE_BITMAP(bmap, 192);
+
+	bitmap_set(bmap, 0, 192);
+
+	bitmap_clear(bmap, 0, 8);
+	__clear_bit(50, bmap);
+	bitmap_clear(bmap, 60, 18);
+	__set_bit(69, bmap);
+	__clear_bit(80, bmap);
+	bitmap_clear(bmap, 100, 10);
+	__clear_bit(120, bmap);
+	bitmap_clear(bmap, 145, 8);
+	bitmap_clear(bmap, 160, 32);
+
+	expect_eq_uint(0,
+		bitmap_find_next_zero_area_off(bmap, 192, 0, 8, 0, 0));
+	expect_eq_uint(0,
+		bitmap_find_next_zero_area_off(bmap, 192, 0, 8, 3, 0));
+	expect_eq_uint(163,
+		bitmap_find_next_zero_area_off(bmap, 192, 0, 8, 3, 1));
+	expect_eq_uint(60,
+		bitmap_find_next_zero_area_off(bmap, 192, 1, 8, 0, 0));
+	expect_eq_uint(160,
+		bitmap_find_next_zero_area_off(bmap, 192, 1, 8, 7, 0));
+	expect_eq_uint(60,
+		bitmap_find_next_zero_area_off(bmap, 192, 1, 8, 7, 4));
+	expect_eq_uint(100,
+		bitmap_find_next_zero_area_off(bmap, 192, 0, 10, 0, 0));
+	expect_eq_uint(160,
+		bitmap_find_next_zero_area_off(bmap, 192, 0, 32, 0, 0));
+	expect_eq_uint(1,
+		!!(bitmap_find_next_zero_area_off(bmap, 192, 0, 33, 0, 0) >= 192));
+}
+
 static void __init test_fill_set(void)
 {
 	DECLARE_BITMAP(bmap, 1024);
@@ -1559,6 +1596,7 @@ static void __init selftest(void)
 	test_for_each_clear_bitrange_from();
 	test_for_each_set_clump8();
 	test_for_each_set_bit_wrap();
+	test_bitmap_find_next_zero_area_off();
 }
 
 KSTM_MODULE_LOADERS(test_bitmap);
-- 
2.34.1


  reply	other threads:[~2026-06-22  3:01 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-22  3:00 [PATCH v7 0/2] Improve the performance of bitmap_find_next_zero_area_off() Yi Sun
2026-06-22  3:00 ` Yi Sun [this message]
2026-06-22 10:05   ` [PATCH v7 1/2] lib: bitmap: add tests for bitmap_find_next_zero_area_off() Michał Nazarewicz
2026-06-22 12:39     ` 答复: " 孙毅 (Yi Sun)
2026-06-22  3:00 ` [PATCH v7 2/2] lib: bitmap: optimize bitmap_find_next_zero_area_off() Yi Sun
2026-06-22  9:56   ` Michał Nazarewicz
2026-06-30 20:52   ` Nathan Chancellor
2026-06-30 23:13     ` Yury Norov
2026-07-04  9:12     ` yi.sun
2026-07-04 22:03       ` Yury Norov

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