From: Xi Ruoyao <xry111@xry111.site>
To: Huacai Chen <chenhuacai@kernel.org>, WANG Xuerui <kernel@xen0n.name>
Cc: loongarch@lists.linux.dev, linux-kernel@vger.kernel.org,
Tiezhu Yang <yangtiezhu@loongson.cn>,
Xi Ruoyao <xry111@xry111.site>
Subject: [PATCH] LoongArch: Select ARCH_HAS_FAST_MULTIPLIER
Date: Thu, 28 Mar 2024 01:18:07 +0800 [thread overview]
Message-ID: <20240327171807.27741-1-xry111@xry111.site> (raw)
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
next reply other threads:[~2024-03-27 17:18 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-27 17:18 Xi Ruoyao [this message]
2024-03-29 2:09 ` [PATCH] LoongArch: Select ARCH_HAS_FAST_MULTIPLIER Huacai Chen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20240327171807.27741-1-xry111@xry111.site \
--to=xry111@xry111.site \
--cc=chenhuacai@kernel.org \
--cc=kernel@xen0n.name \
--cc=linux-kernel@vger.kernel.org \
--cc=loongarch@lists.linux.dev \
--cc=yangtiezhu@loongson.cn \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.