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 <[email protected]>
---
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
Queued for loongarch-next, thanks.
Huacai
On Thu, Mar 28, 2024 at 1:18 AM Xi Ruoyao <[email protected]> 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 <[email protected]>
> ---
> 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
>