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From:   Ard Biesheuvel <ardb@kernel.org>
Date:   Tue, 13 Dec 2022 17:56:02 +0100
Message-ID: <CAMj1kXHad8wRd9_P7A1Oo8Ucw0H=+19ffO4mss7eouivNwy1vg@mail.gmail.com>
Subject: Re: [PATCH v2 0/2] ARM: allow kernel mode NEON in softirq context
To:     Martin Willi <martin@strongswan.org>
Cc:     linux-arm-kernel@lists.infradead.org, linux@armlinux.org.uk,
        linux-crypto@vger.kernel.org,
        Linus Walleij <linus.walleij@linaro.org>,
        Arnd Bergmann <arnd@arndb.de>
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On Mon, 12 Dec 2022 at 15:38, Martin Willi <martin@strongswan.org> wrote:
>
> Hi Ard,
>
> > Currently on ARM, we only permit kernel mode NEON in task context [...]
> > For IPsec packet encryption involving highly performant crypto
> > implementations, this results in a substantial performance hit [...]
>
> Thanks for your continued work on this.
>
> > Without these changes, an IPsec tunnel from a 32-bit VM to the 64-bit
> > host can achieve a throughput of 9.5 MB/s TX and 11.9 MB/s RX.
> >
> > When the crypto algorithm is permitted to execute in softirq context,
> > the throughput increases to 16.5 MB/s TX and 41 MB/s RX.
>
> In my tests on an Armada 385, I could increase IPsec throughput with
> ChaCha20/Poly1305 on RX from ~230 to ~260 MBit/s when using the NEON
> code path. So you may add my:
>
> Tested-by: Martin Willi <martin@strongswan.org>
>

Thanks!