From: Jisheng Zhang <jszhang3@mail.ustc.edu.cn>
To: Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>
Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] riscv: enable GENERIC_FIND_FIRST_BIT
Date: Wed, 8 Sep 2021 23:04:27 +0800 [thread overview]
Message-ID: <20210908230427.3a92fb87@xhacker> (raw)
In-Reply-To: <20210718001423.6b8e1d23@xhacker>
Hi Palmer,
On Sun, 18 Jul 2021 00:14:23 +0800
Jisheng Zhang wrote:
> From: Jisheng Zhang <jszhang@kernel.org>
>
> riscv doesn't implement architecture-optimized bitsearching functions
> such as find_first_{zero}_bit() etc.
>
> When GENERIC_FIND_FIRST_BIT=n, find_first_bit() is implemented with
> find_next_bit() which is less efficient. Enable GENERIC_FIND_FIRST_BIT
> for riscv to get more optimized find_first_bit() implementation, an
> initial test(lib/find_bit_benchmark) shows find_first_bit() performance
> is improved by nearly 32%.
It seems this patch is missed. Is it possible to pick it up for 2nd 5.15-rc1 PR?
Thanks
>
> Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
> ---
> arch/riscv/Kconfig | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index 8fcceb8eda07..7ebc54c5c245 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -47,6 +47,7 @@ config RISCV
> select GENERIC_ATOMIC64 if !64BIT
> select GENERIC_CLOCKEVENTS_BROADCAST if SMP
> select GENERIC_EARLY_IOREMAP
> + select GENERIC_FIND_FIRST_BIT
> select GENERIC_GETTIMEOFDAY if HAVE_GENERIC_VDSO
> select GENERIC_IOREMAP
> select GENERIC_IRQ_MULTI_HANDLER
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next prev parent reply other threads:[~2021-09-08 15:11 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-17 16:14 [PATCH] riscv: enable GENERIC_FIND_FIRST_BIT Jisheng Zhang
2021-09-08 15:04 ` Jisheng Zhang [this message]
2021-09-09 0:58 ` Kefeng Wang
2021-09-09 13:49 ` Jisheng Zhang
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