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Subject: Re: [PATCH 1/1] arm64: Accelerate Adler32 using arm64 SVE
 instructions.
To:     Ard Biesheuvel <ardb@kernel.org>
CC:     Eric Biggers <ebiggers@kernel.org>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        "David S. Miller" <davem@davemloft.net>,
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        Will Deacon <will@kernel.org>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Alexandre Torgue <alexandre.torgue@st.com>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Linux Crypto Mailing List <linux-crypto@vger.kernel.org>
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 <CAMj1kXG+YJvHLFDMk7ABAD=WthxLx5Uh0LAXCP6+2tXEySj7eg@mail.gmail.com>
From:   Li Qiang <liqiang64@huawei.com>
Message-ID: <5b528637-5cb9-a134-2936-7925afae95c6@huawei.com>
Date:   Thu, 5 Nov 2020 17:05:53 +0800
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在 2020/11/5 15:51, Ard Biesheuvel 写道:
> Note that NEON intrinsics can be compiled for 32-bit ARM as well (with
> a bit of care - please refer to lib/raid6/recov_neon_inner.c for an
> example of how to deal with intrinsics that are only available on
> arm64) and are less error prone, so intrinsics should be preferred if
> feasible.
> 
> However, you have still not explained how optimizing Adler32 makes a
> difference for a real-world use case. Where is libdeflate used on a
> hot path?
> .

Sorry :(, I have not specifically searched for the use of this algorithm
in the kernel.

When I used perf to test the performance of the libz library before,
I saw that the adler32 algorithm occupies a lot of hot spots.I just
saw this algorithm used in the kernel code, so I think optimizing this
algorithm may have some positive optimization effects on the kernel.:)

-- 
Best regards,
Li Qiang