From: Tao Cui <cuitao@kylinos.cn>
To: Huacai Chen <chenhuacai@kernel.org>, Bibo Mao <maobibo@loongson.cn>
Cc: zhaotianrui@loongson.cn, loongarch@lists.linux.dev, kernel@xen0n.name
Subject: Re: [PATCH] LoongArch/KVM: Simplify _kvm_pte_init with memset64
Date: Wed, 29 Apr 2026 16:23:11 +0800 [thread overview]
Message-ID: <08049275-494f-46e1-8f74-5c5451f1fd17@kylinos.cn> (raw)
In-Reply-To: <CAAhV-H5Hat1rJywzw2CoLZYf=+hXea35zsvT+xyBOxPVk0z0ZA@mail.gmail.com>
>>>
>> what is the benefit of memset64() here? I think that 8x loop unrolling
>> is better from performance side. The page size is 16K or 4K and buffer
>> is large enough, unrolling seems to be better.
> I agree.
>
> Huacai
>>
>> Regards
>> Bibo Mao
>>
Thanks a lot for your review, Bibo and Huacai.
You are absolutely right. When I looked at the usage of this function, I only intended to make the implementation functionally simpler, but overlooked the performance benefits of the loop unrolling. With PTRS_PER_PTE = 2048, the generic implementation is indeed less performant than the current version with 8-fold loop unrolling.
Thanks.
--
Tao Cui
prev parent reply other threads:[~2026-04-29 8:23 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-28 13:11 [PATCH] LoongArch/KVM: Simplify _kvm_pte_init with memset64 Tao Cui
2026-04-29 7:31 ` Bibo Mao
2026-04-29 7:41 ` Huacai Chen
2026-04-29 8:23 ` Tao Cui [this message]
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