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From: Huacai Chen <chenhuacai@kernel.org>
To: Xi Ruoyao <xry111@xry111.site>
Cc: WANG Xuerui <kernel@xen0n.name>,
	loongarch@lists.linux.dev,  linux-kernel@vger.kernel.org,
	Tiezhu Yang <yangtiezhu@loongson.cn>
Subject: Re: [PATCH] LoongArch: Select ARCH_HAS_FAST_MULTIPLIER
Date: Fri, 29 Mar 2024 10:09:46 +0800	[thread overview]
Message-ID: <CAAhV-H77h3gE_tDKiFYhDC4NbB9ain=sGCemeJ54y8aqvvmrMw@mail.gmail.com> (raw)
In-Reply-To: <20240327171807.27741-1-xry111@xry111.site>

Queued for loongarch-next, thanks.

Huacai

On Thu, Mar 28, 2024 at 1:18 AM Xi Ruoyao <xry111@xry111.site> wrote:
>
> LA464 and LA664 can do 32-bit/64-bit integer multiplication with a
> latency of 4 cycles and a throughput of 2 ops per cycle.  It's
> comparable to mainstream x86 and arm64 cores, so select
> ARCH_HAS_FAST_MULTIPLIER like them.
>
> It speeds up __sw_hweight32 in lib/hweight.c for about 14% on LA464 and
> 11% on LA664, and __sw_hweight64 for about 30% on LA464 and 33% on
> LA664.
>
> Signed-off-by: Xi Ruoyao <xry111@xry111.site>
> ---
>  arch/loongarch/Kconfig | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
> index 5a769bb92d7c..d52a95195e7f 100644
> --- a/arch/loongarch/Kconfig
> +++ b/arch/loongarch/Kconfig
> @@ -16,6 +16,7 @@ config LOONGARCH
>         select ARCH_HAS_ACPI_TABLE_UPGRADE      if ACPI
>         select ARCH_HAS_CPU_FINALIZE_INIT
>         select ARCH_HAS_CURRENT_STACK_POINTER
> +       select ARCH_HAS_FAST_MULTIPLIER
>         select ARCH_HAS_FORTIFY_SOURCE
>         select ARCH_HAS_KCOV
>         select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
> --
> 2.44.0
>

      reply	other threads:[~2024-03-29  2:09 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-27 17:18 [PATCH] LoongArch: Select ARCH_HAS_FAST_MULTIPLIER Xi Ruoyao
2024-03-29  2:09 ` Huacai Chen [this message]

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