From: Yury Norov <yury.norov@gmail.com>
To: Yi Sun <yi.sun@unisoc.com>
Cc: yury.norov@gmail.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, qiang.zhao@freescale.com,
scottwood@freescale.com, fvdl@google.com, tglx@kernel.org,
song@kernel.org, hch@lst.de, minchan@kernel.org,
jstultz@google.com
Subject: Re: [PATCH v6 1/2] lib: bitmap: add tests for bitmap_find_next_zero_area_off()
Date: Thu, 18 Jun 2026 13:31:13 -0400 [thread overview]
Message-ID: <ajQrYZomFpVmcw3v@yury> (raw)
In-Reply-To: <20260618133518.4079981-2-yi.sun@unisoc.com>
On Thu, Jun 18, 2026 at 09:35:17PM +0800, Yi Sun wrote:
> 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 | 31 ++++++++++++++++++++++++-------
> lib/test_bitmap.c | 38 ++++++++++++++++++++++++++++++++++++++
> 2 files changed, 62 insertions(+), 7 deletions(-)
>
> diff --git a/lib/find_bit_benchmark.c b/lib/find_bit_benchmark.c
> index 00d9dc61cd46..cde7c09de05c 100644
> --- a/lib/find_bit_benchmark.c
> +++ b/lib/find_bit_benchmark.c
> @@ -46,7 +46,7 @@ static int __init test_find_first_bit(const void *bitmap, unsigned long len)
> __clear_bit(i, cp);
> }
> time = ktime_get() - time;
> - pr_err("find_first_bit: %18llu ns, %6ld iterations\n", time, cnt);
> + pr_err("find_first_bit: %14llu ns, %6ld iterations\n", time, cnt);
No need to change the existing code. Just add your test and make sure
it looks aligned with the existing format.
>
> return 0;
> }
> @@ -66,7 +66,7 @@ static int __init test_find_first_and_bit(const void *bitmap, const void *bitmap
> __clear_bit(i, cp);
> }
> time = ktime_get() - time;
> - pr_err("find_first_and_bit: %18llu ns, %6ld iterations\n", time, cnt);
> + pr_err("find_first_and_bit: %14llu ns, %6ld iterations\n", time, cnt);
>
> return 0;
> }
> @@ -80,7 +80,7 @@ static int __init test_find_next_bit(const void *bitmap, unsigned long len)
> 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);
> + pr_err("find_next_bit: %14llu ns, %6ld iterations\n", time, cnt);
>
> return 0;
> }
> @@ -94,7 +94,7 @@ static int __init test_find_next_zero_bit(const void *bitmap, unsigned long len)
> 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);
> + pr_err("find_next_zero_bit: %14llu ns, %6ld iterations\n", time, cnt);
>
> return 0;
> }
> @@ -113,7 +113,7 @@ static int __init test_find_last_bit(const void *bitmap, unsigned long len)
> len = l;
> } while (len);
> time = ktime_get() - time;
> - pr_err("find_last_bit: %18llu ns, %6ld iterations\n", time, cnt);
> + pr_err("find_last_bit: %14llu ns, %6ld iterations\n", time, cnt);
>
> return 0;
> }
> @@ -129,7 +129,7 @@ static int __init test_find_nth_bit(const unsigned long *bitmap, unsigned long l
> WARN_ON(l >= len);
> }
> time = ktime_get() - time;
> - pr_err("find_nth_bit: %18llu ns, %6ld iterations\n", time, w);
> + pr_err("find_nth_bit: %14llu ns, %6ld iterations\n", time, w);
>
> return 0;
> }
> @@ -144,7 +144,22 @@ static int __init test_find_next_and_bit(const void *bitmap,
> 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);
> + pr_err("find_next_and_bit: %14llu ns, %6ld iterations\n", time, cnt);
> +
> + 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: %14llu ns, %6ld iterations\n", time, cnt);
>
> return 0;
> }
> @@ -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
next prev parent reply other threads:[~2026-06-18 17:31 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-18 13:35 [PATCH v6 0/2] Improve the performance of bitmap_find_next_zero_area_off() Yi Sun
2026-06-18 13:35 ` [PATCH v6 1/2] lib: bitmap: add tests for bitmap_find_next_zero_area_off() Yi Sun
2026-06-18 17:31 ` Yury Norov [this message]
2026-06-18 13:35 ` [PATCH v6 2/2] lib: bitmap: optimize bitmap_find_next_zero_area_off() Yi Sun
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